Merge pull request #708 from schungx/master

Speed improvement attempts.

.github/workflows/build.yml

@@ -43,28 +43,28 @@ jobs:
         os: [ubuntu-latest]
         flags:
           - ""
-          - "--features debugging"
+          - "--features testing-environ,debugging"
-          - "--features metadata,serde,internals"
+          - "--features testing-environ,metadata,serde,internals"
-          - "--features unchecked,serde,metadata,internals,debugging"
+          - "--features testing-environ,unchecked,serde,metadata,internals,debugging"
-          - "--features sync,serde,metadata,internals,debugging"
+          - "--features testing-environ,sync,serde,metadata,internals,debugging"
-          - "--features no_position,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_position,serde,metadata,internals,debugging"
-          - "--features no_optimize,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_optimize,serde,metadata,internals,debugging"
-          - "--features no_float,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_float,serde,metadata,internals,debugging"
-          - "--features f32_float,serde,metadata,internals,debugging"
+          - "--features testing-environ,f32_float,serde,metadata,internals,debugging"
-          - "--features decimal,serde,metadata,internals,debugging"
+          - "--features testing-environ,decimal,serde,metadata,internals,debugging"
-          - "--features no_custom_syntax,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_custom_syntax,serde,metadata,internals,debugging"
-          - "--features no_float,decimal"
+          - "--features testing-environ,no_float,decimal"
-          - "--tests --features only_i32,serde,metadata,internals,debugging"
+          - "--tests --features testing-environ,only_i32,serde,metadata,internals,debugging"
-          - "--features only_i64,serde,metadata,internals,debugging"
+          - "--features testing-environ,only_i64,serde,metadata,internals,debugging"
-          - "--features no_index,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_index,serde,metadata,internals,debugging"
-          - "--features no_object,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_object,serde,metadata,internals,debugging"
-          - "--features no_function,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_function,serde,metadata,internals,debugging"
-          - "--features no_module,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_module,serde,metadata,internals,debugging"
-          - "--features no_time,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_time,serde,metadata,internals,debugging"
-          - "--features no_closure,serde,metadata,internals,debugging"
+          - "--features testing-environ,no_closure,serde,metadata,internals,debugging"
-          - "--features unicode-xid-ident,serde,metadata,internals,debugging"
+          - "--features testing-environ,unicode-xid-ident,serde,metadata,internals,debugging"
-          - "--features sync,no_time,no_function,no_float,no_position,no_optimize,no_module,no_closure,no_custom_syntax,metadata,serde,unchecked,debugging"
+          - "--features testing-environ,sync,no_time,no_function,no_float,no_position,no_optimize,no_module,no_closure,no_custom_syntax,metadata,serde,unchecked,debugging"
-          - "--features no_time,no_function,no_float,no_position,no_index,no_object,no_optimize,no_module,no_closure,no_custom_syntax,unchecked"
+          - "--features testing-environ,no_time,no_function,no_float,no_position,no_index,no_object,no_optimize,no_module,no_closure,no_custom_syntax,unchecked"
         toolchain: [stable]
         experimental: [false]
         include:

.gitignore

@@ -6,6 +6,7 @@ benches/results
 clippy.toml
 Rhai.toml
 **/*.bat
+**/*.exe
 doc/rhai-sync.json
 doc/rhai.json
 .idea/

CHANGELOG.md

@@ -12,11 +12,26 @@ Bug fixes
 * Syntax such as `foo.bar::baz` no longer panics, but returns a proper parse error.
 * `x += y` where `x` and `y` are `char` now works correctly.
 * Expressions such as `!inside` now parses correctly instead of as `!in` followed by `side`.
+* Custom syntax starting with symbols now works correctly and no longer raises a parse error.
+* Comparing different custom types now works correctly when the appropriate comparison operators are registered.
+* Op-assignments to bit flags or bit ranges now work correctly.
+
+Potentially breaking changes
+----------------------------
+
+* The trait method `ModuleResolver::resolve_raw` (which is a low-level API) now takes a `&mut Scope` parameter.  This is a breaking change because the signature is modified, but this trait method has a default and is rarely called/implemented in practice.
+* `Module::eval_ast_as_new_raw` (a low-level API) now takes a `&mut Scope` instead of the `Scope` parameter.  This is a breaking change because the `&mut` is now required.
+* `Engine::allow_loop_expressions` now correctly defaults to `true` (was erroneously `false` by default).
 
 Enhancements
 ------------
 
+* `Engine::new_raw` is now `const` and runs very fast, delaying all other initialization until first use.
 * The functions `min` and `max` are added for numbers.
+* Range cases in `switch` statements now also match floating-point and decimal values. In order to support this, however, small numeric ranges cases are no longer unrolled.
+* Loading a module via `import` now gives the module access to the current scope, including variables and constants defined inside.
+* Some very simple operator calls (e.g. integer add) are short-circuited to avoid the overhead of a function call, resulting in a small speed improvement.
+* The tokenizer now uses table-driven keyword recognizers generated by GNU gperf. At least _theoretically_ it should be faster...
 
 
 Version 1.12.0

Cargo.toml

@@ -34,7 +34,7 @@ serde_json = { version = "1.0", default-features = false, features = ["alloc"],
 unicode-xid = { version = "0.2", default-features = false, optional = true }
 rust_decimal = { version = "1.16", default-features = false, features = ["maths"], optional = true }
 getrandom = { version = "0.2", optional = true }
-rustyline = { version = "10", optional = true }
+rustyline = { version = "11", optional = true }
 document-features = { version = "0.2", optional = true }
 
 [dev-dependencies]
@@ -117,6 +117,11 @@ std = ["ahash/std", "num-traits/std", "smartstring/std"]
     ## Use [`stdweb`](https://crates.io/crates/stdweb) as JavaScript interface.
     stdweb = ["getrandom/js", "instant/stdweb"]
 
+#! ### Features used in testing environments only
+
+    ## Running under a testing environment.
+    testing-environ = []
+
 [[bin]]
 name = "rhai-repl"
 required-features = ["rustyline"]
@@ -151,4 +156,4 @@ features = ["document-features", "metadata", "serde", "internals", "decimal", "d
 [patch.crates-io]
 # Notice that a custom modified version of `rustyline` is used which supports bracketed paste on Windows.
 # This can be moved to the official version when bracketed paste is added.
-rustyline = { git = "https://github.com/schungx/rustyline", branch = "v10" }
+rustyline = { git = "https://github.com/schungx/rustyline", branch = "v11" }

codegen/ui_tests/non_clonable.stderr

@@ -1,14 +1,14 @@
 error[E0277]: the trait bound `NonClonable: Clone` is not satisfied
-    --> ui_tests/non_clonable.rs:11:23
+  --> ui_tests/non_clonable.rs:11:23
-     |
+   |
-11   | pub fn test_fn(input: NonClonable) -> bool {
+11 | pub fn test_fn(input: NonClonable) -> bool {
-     |                       ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
+   |                       ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
-     |
+   |
 note: required by a bound in `rhai::Dynamic::cast`
-    --> $WORKSPACE/src/types/dynamic.rs
+  --> $WORKSPACE/src/types/dynamic.rs
-     |
+   |
-     |     pub fn cast<T: Any + Clone>(self) -> T {
+   |     pub fn cast<T: Any + Clone>(self) -> T {
-     |                          ^^^^^ required by this bound in `rhai::Dynamic::cast`
+   |                          ^^^^^ required by this bound in `Dynamic::cast`
 help: consider annotating `NonClonable` with `#[derive(Clone)]`
      |
 3    | #[derive(Clone)]

codegen/ui_tests/non_clonable_second.stderr

@@ -1,14 +1,14 @@
 error[E0277]: the trait bound `NonClonable: Clone` is not satisfied
-    --> ui_tests/non_clonable_second.rs:11:27
+  --> ui_tests/non_clonable_second.rs:11:27
-     |
+   |
-11   | pub fn test_fn(a: u32, b: NonClonable) -> bool {
+11 | pub fn test_fn(a: u32, b: NonClonable) -> bool {
-     |                           ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
+   |                           ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
-     |
+   |
 note: required by a bound in `rhai::Dynamic::cast`
-    --> $WORKSPACE/src/types/dynamic.rs
+  --> $WORKSPACE/src/types/dynamic.rs
-     |
+   |
-     |     pub fn cast<T: Any + Clone>(self) -> T {
+   |     pub fn cast<T: Any + Clone>(self) -> T {
-     |                          ^^^^^ required by this bound in `rhai::Dynamic::cast`
+   |                          ^^^^^ required by this bound in `Dynamic::cast`
 help: consider annotating `NonClonable` with `#[derive(Clone)]`
      |
 3    | #[derive(Clone)]

codegen/ui_tests/rhai_fn_non_clonable_return.stderr

@@ -1,17 +1,17 @@
 error[E0277]: the trait bound `NonClonable: Clone` is not satisfied
-    --> ui_tests/rhai_fn_non_clonable_return.rs:11:31
+  --> ui_tests/rhai_fn_non_clonable_return.rs:11:31
-     |
+   |
-10   | #[export_fn]
+10 | #[export_fn]
-     | ------------ in this procedural macro expansion
+   | ------------ in this procedural macro expansion
-11   | pub fn test_fn(input: f32) -> NonClonable {
+11 | pub fn test_fn(input: f32) -> NonClonable {
-     |                               ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
+   |                               ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
-     |
+   |
 note: required by a bound in `rhai::Dynamic::from`
-    --> $WORKSPACE/src/types/dynamic.rs
+  --> $WORKSPACE/src/types/dynamic.rs
-     |
+   |
-     |     pub fn from<T: Variant + Clone>(value: T) -> Self {
+   |     pub fn from<T: Variant + Clone>(value: T) -> Self {
-     |                              ^^^^^ required by this bound in `rhai::Dynamic::from`
+   |                              ^^^^^ required by this bound in `Dynamic::from`
-     = note: this error originates in the attribute macro `export_fn` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the attribute macro `export_fn` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider annotating `NonClonable` with `#[derive(Clone)]`
      |
 3    | #[derive(Clone)]

codegen/ui_tests/rhai_mod_non_clonable_return.stderr

@@ -1,18 +1,18 @@
 error[E0277]: the trait bound `NonClonable: Clone` is not satisfied
-    --> ui_tests/rhai_mod_non_clonable_return.rs:12:35
+  --> ui_tests/rhai_mod_non_clonable_return.rs:12:35
-     |
+   |
-10   | #[export_module]
+10 | #[export_module]
-     | ---------------- in this procedural macro expansion
+   | ---------------- in this procedural macro expansion
-11   | pub mod test_mod {
+11 | pub mod test_mod {
-12   |     pub fn test_fn(input: f32) -> NonClonable {
+12 |     pub fn test_fn(input: f32) -> NonClonable {
-     |                                   ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
+   |                                   ^^^^^^^^^^^ the trait `Clone` is not implemented for `NonClonable`
-     |
+   |
 note: required by a bound in `rhai::Dynamic::from`
-    --> $WORKSPACE/src/types/dynamic.rs
+  --> $WORKSPACE/src/types/dynamic.rs
-     |
+   |
-     |     pub fn from<T: Variant + Clone>(value: T) -> Self {
+   |     pub fn from<T: Variant + Clone>(value: T) -> Self {
-     |                              ^^^^^ required by this bound in `rhai::Dynamic::from`
+   |                              ^^^^^ required by this bound in `Dynamic::from`
-     = note: this error originates in the attribute macro `export_module` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the attribute macro `export_module` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider annotating `NonClonable` with `#[derive(Clone)]`
      |
 3    | #[derive(Clone)]

src/README.md

@@ -28,4 +28,5 @@ Sub-Directories
 | `func`        | Support for function calls                            |
 | `eval`        | Evaluation engine                                     |
 | `serde`       | Support for [`serde`](https://crates.io/crates/serde) |
+| `tools`       | External tools needed for building                    |
 | `bin`         | Pre-built CLI binaries (e.g. `rhai-run`, `rhai-repl`) |

src/api/compile.rs

@@ -2,6 +2,7 @@
 
 use crate::func::native::locked_write;
 use crate::parser::{ParseResult, ParseState};
+use crate::types::StringsInterner;
 use crate::{Engine, OptimizationLevel, Scope, AST};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -126,7 +127,7 @@ impl Engine {
                 let path = path.clone();
 
                 match self
-                    .module_resolver
+                    .module_resolver()
                     .resolve_ast(self, None, &path, crate::Position::NONE)
                 {
                     Some(Ok(module_ast)) => collect_imports(&module_ast, &resolver, &mut imports),
@@ -135,7 +136,7 @@ impl Engine {
                 }
 
                 let module =
-                    self.module_resolver
+                    self.module_resolver()
                         .resolve(self, None, &path, crate::Position::NONE)?;
 
                 let module = shared_take_or_clone(module);
@@ -223,7 +224,17 @@ impl Engine {
         optimization_level: OptimizationLevel,
     ) -> ParseResult<AST> {
         let (stream, tc) = self.lex_raw(scripts.as_ref(), self.token_mapper.as_deref());
-        let interned_strings = &mut *locked_write(&self.interned_strings);
+
+        let mut interner;
+        let mut guard;
+        let interned_strings = if let Some(ref interner) = self.interned_strings {
+            guard = locked_write(interner);
+            &mut *guard
+        } else {
+            interner = StringsInterner::new();
+            &mut interner
+        };
+
         let state = &mut ParseState::new(scope, interned_strings, tc);
         let mut _ast = self.parse(stream.peekable(), state, optimization_level)?;
         #[cfg(feature = "metadata")]
@@ -294,7 +305,17 @@ impl Engine {
     ) -> ParseResult<AST> {
         let scripts = [script];
         let (stream, t) = self.lex_raw(&scripts, self.token_mapper.as_deref());
-        let interned_strings = &mut *locked_write(&self.interned_strings);
+
+        let mut interner;
+        let mut guard;
+        let interned_strings = if let Some(ref interner) = self.interned_strings {
+            guard = locked_write(interner);
+            &mut *guard
+        } else {
+            interner = StringsInterner::new();
+            &mut interner
+        };
+
         let state = &mut ParseState::new(Some(scope), interned_strings, t);
         self.parse_global_expr(stream.peekable(), state, |_| {}, self.optimization_level)
     }

src/api/custom_syntax.rs

@@ -232,7 +232,7 @@ impl Engine {
             }
 
             let token = Token::lookup_symbol_from_syntax(s).or_else(|| {
-                if is_reserved_keyword_or_symbol(s) {
+                if is_reserved_keyword_or_symbol(s).0 {
                     Some(Token::Reserved(Box::new(s.into())))
                 } else {
                     None
@@ -255,7 +255,8 @@ impl Engine {
                 // Markers not in first position
                 #[cfg(not(feature = "no_float"))]
                 CUSTOM_SYNTAX_MARKER_FLOAT if !segments.is_empty() => s.into(),
-                // Standard or reserved keyword/symbol not in first position
+
+                // Keyword/symbol not in first position
                 _ if !segments.is_empty() && token.is_some() => {
                     // Make it a custom keyword/symbol if it is disabled or reserved
                     if (self
@@ -274,6 +275,7 @@ impl Engine {
                     }
                     s.into()
                 }
+
                 // Standard keyword in first position but not disabled
                 _ if segments.is_empty()
                     && token.as_ref().map_or(false, Token::is_standard_keyword)
@@ -291,8 +293,11 @@ impl Engine {
                     )
                     .into_err(Position::NONE));
                 }
-                // Identifier in first position
+
-                _ if segments.is_empty() && is_valid_identifier(s) => {
+                // Identifier or symbol in first position
+                _ if segments.is_empty()
+                    && (is_valid_identifier(s) || is_reserved_keyword_or_symbol(s).0) =>
+                {
                     // Make it a custom keyword/symbol if it is disabled or reserved
                     if self
                         .disabled_symbols
@@ -310,6 +315,7 @@ impl Engine {
                     }
                     s.into()
                 }
+
                 // Anything else is an error
                 _ => {
                     return Err(LexError::ImproperSymbol(
@@ -326,23 +332,20 @@ impl Engine {
             segments.push(seg);
         }
 
-        // If the syntax has no symbols, just ignore the registration
+        // If the syntax has nothing, just ignore the registration
         if segments.is_empty() {
             return Ok(self);
         }
 
-        // The first keyword is the discriminator
+        // The first keyword/symbol is the discriminator
         let key = segments[0].clone();
 
         self.register_custom_syntax_with_state_raw(
             key,
             // Construct the parsing function
-            move |stream, _, _| {
+            move |stream, _, _| match stream.len() {
-                if stream.len() >= segments.len() {
+                len if len >= segments.len() => Ok(None),
-                    Ok(None)
+                len => Ok(Some(segments[len].clone())),
-                } else {
-                    Ok(Some(segments[stream.len()].clone()))
-                }
             },
             scope_may_be_changed,
             move |context, expressions, _| func(context, expressions),
@@ -399,7 +402,8 @@ impl Engine {
                     parse: Box::new(parse),
                     func: Box::new(func),
                     scope_may_be_changed,
-                },
+                }
+                .into(),
             );
         self
     }

src/api/eval.rs

@@ -4,6 +4,7 @@ use crate::eval::{Caches, GlobalRuntimeState};
 use crate::func::native::locked_write;
 use crate::parser::ParseState;
 use crate::types::dynamic::Variant;
+use crate::types::StringsInterner;
 use crate::{
     Dynamic, Engine, OptimizationLevel, Position, RhaiResult, RhaiResultOf, Scope, AST, ERR,
 };
@@ -119,7 +120,15 @@ impl Engine {
     ) -> RhaiResultOf<T> {
         let scripts = [script];
         let ast = {
-            let interned_strings = &mut *locked_write(&self.interned_strings);
+            let mut interner;
+            let mut guard;
+            let interned_strings = if let Some(ref interner) = self.interned_strings {
+                guard = locked_write(interner);
+                &mut *guard
+            } else {
+                interner = StringsInterner::new();
+                &mut interner
+            };
 
             let (stream, tc) = self.lex_raw(&scripts, self.token_mapper.as_deref());
 

src/api/events.rs

@@ -286,7 +286,7 @@ impl Engine {
     /// ```
     #[inline(always)]
     pub fn on_print(&mut self, callback: impl Fn(&str) + SendSync + 'static) -> &mut Self {
-        self.print = Box::new(callback);
+        self.print = Some(Box::new(callback));
         self
     }
     /// Override default action of `debug` (print to stdout using [`println!`])
@@ -336,7 +336,7 @@ impl Engine {
         &mut self,
         callback: impl Fn(&str, Option<&str>, Position) + SendSync + 'static,
     ) -> &mut Self {
-        self.debug = Box::new(callback);
+        self.debug = Some(Box::new(callback));
         self
     }
     /// _(debugging)_ Register a callback for debugging.
@@ -363,7 +363,7 @@ impl Engine {
             + SendSync
             + 'static,
     ) -> &mut Self {
-        self.debugger_interface = Some(Box::new((Box::new(init), Box::new(callback))));
+        self.debugger_interface = Some((Box::new(init), Box::new(callback)));
         self
     }
 }

src/api/json.rs

@@ -4,6 +4,7 @@
 use crate::func::native::locked_write;
 use crate::parser::{ParseSettingFlags, ParseState};
 use crate::tokenizer::Token;
+use crate::types::StringsInterner;
 use crate::{Engine, LexError, Map, OptimizationLevel, RhaiResultOf};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -115,7 +116,16 @@ impl Engine {
         );
 
         let ast = {
-            let interned_strings = &mut *locked_write(&self.interned_strings);
+            let mut interner;
+            let mut guard;
+            let interned_strings = if let Some(ref interner) = self.interned_strings {
+                guard = locked_write(interner);
+                &mut *guard
+            } else {
+                interner = StringsInterner::new();
+                &mut interner
+            };
+
             let state = &mut ParseState::new(None, interned_strings, tokenizer_control);
 
             self.parse_global_expr(

src/api/mod.rs

@@ -54,7 +54,10 @@ impl Engine {
     #[inline(always)]
     #[must_use]
     pub fn module_resolver(&self) -> &dyn crate::ModuleResolver {
-        &*self.module_resolver
+        static DUMMY_RESOLVER: crate::module::resolvers::DummyModuleResolver =
+            crate::module::resolvers::DummyModuleResolver;
+
+        self.module_resolver.as_deref().unwrap_or(&DUMMY_RESOLVER)
     }
 
     /// Set the module resolution service used by the [`Engine`].
@@ -66,7 +69,7 @@ impl Engine {
         &mut self,
         resolver: impl crate::ModuleResolver + 'static,
     ) -> &mut Self {
-        self.module_resolver = Box::new(resolver);
+        self.module_resolver = Some(Box::new(resolver));
         self
     }
 

src/api/optimize.rs

@@ -63,7 +63,11 @@ impl Engine {
         );
 
         #[cfg(feature = "metadata")]
-        _new_ast.set_doc(std::mem::take(ast.doc_mut()));
+        if let Some(doc) = ast.doc_mut() {
+            _new_ast.set_doc(std::mem::take(doc));
+        } else {
+            _new_ast.clear_doc();
+        }
 
         _new_ast
     }

src/api/options.rs

@@ -38,23 +38,26 @@ impl LangOptions {
     /// Create a new [`LangOptions`] with default values.
     #[inline(always)]
     #[must_use]
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
-        Self::IF_EXPR
+        Self::from_bits_truncate(
-            | Self::SWITCH_EXPR
+            Self::IF_EXPR.bits()
-            | Self::STMT_EXPR
+                | Self::SWITCH_EXPR.bits()
-            | Self::LOOPING
+                | Self::LOOP_EXPR.bits()
-            | Self::SHADOWING
+                | Self::STMT_EXPR.bits()
-            | Self::FAST_OPS
+                | Self::LOOPING.bits()
-            | {
+                | Self::SHADOWING.bits()
-                #[cfg(not(feature = "no_function"))]
+                | Self::FAST_OPS.bits()
-                {
+                | {
-                    Self::ANON_FN
+                    #[cfg(not(feature = "no_function"))]
-                }
+                    {
-                #[cfg(feature = "no_function")]
+                        Self::ANON_FN.bits()
-                {
+                    }
-                    Self::empty()
+                    #[cfg(feature = "no_function")]
-                }
+                    {
-            }
+                        Self::empty().bits()
+                    }
+                },
+        )
     }
 }
 

src/api/register.rs

@@ -1,6 +1,7 @@
 //! Module that defines the public function/module registration API of [`Engine`].
 
 use crate::func::{FnCallArgs, RegisterNativeFunction, SendSync};
+use crate::module::ModuleFlags;
 use crate::types::dynamic::Variant;
 use crate::{
     Engine, FnAccess, FnNamespace, Identifier, Module, NativeCallContext, RhaiResultOf, Shared,
@@ -14,20 +15,18 @@ use std::prelude::v1::*;
 use crate::func::register::Mut;
 
 impl Engine {
-    /// Get the global namespace module (which is the fist module in `global_modules`).
-    #[inline(always)]
-    #[allow(dead_code)]
-    #[must_use]
-    pub(crate) fn global_namespace(&self) -> &Module {
-        self.global_modules.first().unwrap()
-    }
     /// Get a mutable reference to the global namespace module
     /// (which is the first module in `global_modules`).
     #[inline(always)]
     #[must_use]
-    pub(crate) fn global_namespace_mut(&mut self) -> &mut Module {
+    fn global_namespace_mut(&mut self) -> &mut Module {
-        let module = self.global_modules.first_mut().unwrap();
+        if self.global_modules.is_empty() {
-        Shared::get_mut(module).expect("not shared")
+            let mut global_namespace = Module::new();
+            global_namespace.flags |= ModuleFlags::INTERNAL;
+            self.global_modules.push(global_namespace.into());
+        }
+
+        Shared::get_mut(self.global_modules.first_mut().unwrap()).expect("not shared")
     }
     /// Register a custom function with the [`Engine`].
     ///
@@ -677,6 +676,9 @@ impl Engine {
     /// modules are searched in reverse order.
     #[inline(always)]
     pub fn register_global_module(&mut self, module: SharedModule) -> &mut Self {
+        // Make sure the global namespace is created.
+        let _ = self.global_namespace_mut();
+
         // Insert the module into the front.
         // The first module is always the global namespace.
         self.global_modules.insert(1, module);
@@ -729,7 +731,7 @@ impl Engine {
             name: &str,
             module: SharedModule,
         ) {
-            let separator = crate::tokenizer::Token::DoubleColon.literal_syntax();
+            let separator = crate::engine::NAMESPACE_SEPARATOR;
 
             if name.contains(separator) {
                 let mut iter = name.splitn(2, separator);
@@ -779,7 +781,9 @@ impl Engine {
     pub fn gen_fn_signatures(&self, include_packages: bool) -> Vec<String> {
         let mut signatures = Vec::with_capacity(64);
 
-        signatures.extend(self.global_namespace().gen_fn_signatures());
+        if let Some(global_namespace) = self.global_modules.first() {
+            signatures.extend(global_namespace.gen_fn_signatures());
+        }
 
         #[cfg(not(feature = "no_module"))]
         for (name, m) in self.global_sub_modules.as_deref().into_iter().flatten() {

src/api/run.rs

@@ -3,6 +3,7 @@
 use crate::eval::{Caches, GlobalRuntimeState};
 use crate::func::native::locked_write;
 use crate::parser::ParseState;
+use crate::types::StringsInterner;
 use crate::{Engine, RhaiResultOf, Scope, AST};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -59,7 +60,17 @@ impl Engine {
         let scripts = [script];
         let ast = {
             let (stream, tc) = self.lex_raw(&scripts, self.token_mapper.as_deref());
-            let interned_strings = &mut *locked_write(&self.interned_strings);
+
+            let mut interner;
+            let mut guard;
+            let interned_strings = if let Some(ref interner) = self.interned_strings {
+                guard = locked_write(interner);
+                &mut *guard
+            } else {
+                interner = StringsInterner::new();
+                &mut interner
+            };
+
             let state = &mut ParseState::new(Some(scope), interned_strings, tc);
             self.parse(stream.peekable(), state, self.optimization_level)?
         };

src/ast/ast.rs

@@ -23,9 +23,9 @@ pub struct AST {
     source: Option<ImmutableString>,
     /// [`AST`] documentation.
     #[cfg(feature = "metadata")]
-    doc: crate::SmartString,
+    doc: Option<Box<crate::SmartString>>,
     /// Global statements.
-    body: StmtBlock,
+    body: Option<Box<StmtBlock>>,
     /// Script-defined functions.
     #[cfg(not(feature = "no_function"))]
     lib: crate::SharedModule,
@@ -54,7 +54,14 @@ impl fmt::Debug for AST {
         #[cfg(not(feature = "no_module"))]
         fp.field("resolver", &self.resolver);
 
-        fp.field("body", &self.body.as_slice());
+        fp.field(
+            "body",
+            &self
+                .body
+                .as_deref()
+                .map(|b| b.as_slice())
+                .unwrap_or_default(),
+        );
 
         #[cfg(not(feature = "no_function"))]
         for (.., fn_def) in self.lib.iter_script_fn() {
@@ -75,11 +82,13 @@ impl AST {
         statements: impl IntoIterator<Item = Stmt>,
         #[cfg(not(feature = "no_function"))] functions: impl Into<crate::SharedModule>,
     ) -> Self {
+        let stmt = StmtBlock::new(statements, Position::NONE, Position::NONE);
+
         Self {
             source: None,
             #[cfg(feature = "metadata")]
-            doc: crate::SmartString::new_const(),
+            doc: None,
-            body: StmtBlock::new(statements, Position::NONE, Position::NONE),
+            body: (!stmt.is_empty()).then(|| stmt.into()),
             #[cfg(not(feature = "no_function"))]
             lib: functions.into(),
             #[cfg(not(feature = "no_module"))]
@@ -95,11 +104,13 @@ impl AST {
         statements: impl IntoIterator<Item = Stmt>,
         #[cfg(not(feature = "no_function"))] functions: impl Into<crate::SharedModule>,
     ) -> Self {
+        let stmt = StmtBlock::new(statements, Position::NONE, Position::NONE);
+
         Self {
             source: None,
             #[cfg(feature = "metadata")]
-            doc: crate::SmartString::new_const(),
+            doc: None,
-            body: StmtBlock::new(statements, Position::NONE, Position::NONE),
+            body: (!stmt.is_empty()).then(|| stmt.into()),
             #[cfg(not(feature = "no_function"))]
             lib: functions.into(),
             #[cfg(not(feature = "no_module"))]
@@ -148,8 +159,8 @@ impl AST {
         Self {
             source: None,
             #[cfg(feature = "metadata")]
-            doc: crate::SmartString::new_const(),
+            doc: None,
-            body: StmtBlock::NONE,
+            body: None,
             #[cfg(not(feature = "no_function"))]
             lib: crate::Module::new().into(),
             #[cfg(not(feature = "no_module"))]
@@ -178,11 +189,7 @@ impl AST {
             .as_mut()
             .map(|m| m.set_id(source.clone()));
 
-        if source.is_empty() {
+        self.source = (!source.is_empty()).then(|| source);
-            self.source = None;
-        } else {
-            self.source = Some(source);
-        }
 
         self
     }
@@ -202,14 +209,14 @@ impl AST {
     #[inline(always)]
     #[must_use]
     pub fn doc(&self) -> &str {
-        &self.doc
+        self.doc.as_ref().map(|s| s.as_str()).unwrap_or_default()
     }
     /// Clear the documentation.
     /// Exported under the `metadata` feature only.
     #[cfg(feature = "metadata")]
     #[inline(always)]
     pub fn clear_doc(&mut self) -> &mut Self {
-        self.doc.clear();
+        self.doc = None;
         self
     }
     /// Get a mutable reference to the documentation.
@@ -219,8 +226,8 @@ impl AST {
     #[inline(always)]
     #[must_use]
     #[allow(dead_code)]
-    pub(crate) fn doc_mut(&mut self) -> &mut crate::SmartString {
+    pub(crate) fn doc_mut(&mut self) -> Option<&mut crate::SmartString> {
-        &mut self.doc
+        self.doc.as_deref_mut()
     }
     /// Set the documentation.
     ///
@@ -228,14 +235,18 @@ impl AST {
     #[cfg(feature = "metadata")]
     #[inline(always)]
     pub(crate) fn set_doc(&mut self, doc: impl Into<crate::SmartString>) {
-        self.doc = doc.into();
+        let doc = doc.into();
+        self.doc = (!doc.is_empty()).then(|| doc.into());
     }
     /// Get the statements.
     #[cfg(not(feature = "internals"))]
     #[inline(always)]
     #[must_use]
     pub(crate) fn statements(&self) -> &[Stmt] {
-        self.body.statements()
+        self.body
+            .as_deref()
+            .map(StmtBlock::statements)
+            .unwrap_or_default()
     }
     /// _(internals)_ Get the statements.
     /// Exported under the `internals` feature only.
@@ -243,14 +254,20 @@ impl AST {
     #[inline(always)]
     #[must_use]
     pub fn statements(&self) -> &[Stmt] {
-        self.body.statements()
+        self.body
+            .as_deref()
+            .map(StmtBlock::statements)
+            .unwrap_or_default()
     }
     /// Extract the statements.
     #[allow(dead_code)]
     #[inline(always)]
     #[must_use]
     pub(crate) fn take_statements(&mut self) -> StmtBlockContainer {
-        self.body.take_statements()
+        self.body
+            .as_deref_mut()
+            .map(StmtBlock::take_statements)
+            .unwrap_or_default()
     }
     /// Does this [`AST`] contain script-defined functions?
     ///
@@ -344,7 +361,7 @@ impl AST {
             source: self.source.clone(),
             #[cfg(feature = "metadata")]
             doc: self.doc.clone(),
-            body: StmtBlock::NONE,
+            body: None,
             lib: lib.into(),
             #[cfg(not(feature = "no_module"))]
             resolver: self.resolver.clone(),
@@ -542,15 +559,15 @@ impl AST {
         other: &Self,
         _filter: impl Fn(FnNamespace, FnAccess, bool, &str, usize) -> bool,
     ) -> Self {
-        let merged = match (self.body.is_empty(), other.body.is_empty()) {
+        let merged = match (&self.body, &other.body) {
-            (false, false) => {
+            (Some(body), Some(other)) => {
-                let mut body = self.body.clone();
+                let mut body = body.as_ref().clone();
-                body.extend(other.body.iter().cloned());
+                body.extend(other.iter().cloned());
                 body
             }
-            (false, true) => self.body.clone(),
+            (Some(body), None) => body.as_ref().clone(),
-            (true, false) => other.body.clone(),
+            (None, Some(body)) => body.as_ref().clone(),
-            (true, true) => StmtBlock::NONE,
+            (None, None) => StmtBlock::NONE,
         };
 
         #[cfg(not(feature = "no_function"))]
@@ -598,11 +615,13 @@ impl AST {
         }
 
         #[cfg(feature = "metadata")]
-        if !other.doc.is_empty() {
+        if let Some(ref other_doc) = other.doc {
-            if !_ast.doc.is_empty() {
+            if let Some(ref mut ast_doc) = _ast.doc {
-                _ast.doc.push('\n');
+                ast_doc.push('\n');
+                ast_doc.push_str(other_doc);
+            } else {
+                _ast.doc = Some(other_doc.clone());
             }
-            _ast.doc.push_str(other.doc());
         }
 
         _ast
@@ -690,7 +709,12 @@ impl AST {
             }
         }
 
-        self.body.extend(other.body.into_iter());
+        match (&mut self.body, other.body) {
+            (Some(body), Some(other)) => body.extend(other.into_iter()),
+            (Some(_), None) => (),
+            (None, body @ Some(_)) => self.body = body,
+            (None, None) => (),
+        }
 
         #[cfg(not(feature = "no_function"))]
         if !other.lib.is_empty() {
@@ -698,11 +722,13 @@ impl AST {
         }
 
         #[cfg(feature = "metadata")]
-        if !other.doc.is_empty() {
+        if let Some(other_doc) = other.doc {
-            if !self.doc.is_empty() {
+            if let Some(ref mut self_doc) = self.doc {
-                self.doc.push('\n');
+                self_doc.push('\n');
+                self_doc.push_str(&other_doc);
+            } else {
+                self.doc = Some(other_doc);
             }
-            self.doc.push_str(&other.doc);
         }
 
         self
@@ -785,7 +811,7 @@ impl AST {
     /// Clear all statements in the [`AST`], leaving only function definitions.
     #[inline(always)]
     pub fn clear_statements(&mut self) -> &mut Self {
-        self.body = StmtBlock::NONE;
+        self.body = None;
         self
     }
     /// Extract all top-level literal constant and/or variable definitions.

src/ast/expr.rs

@@ -185,7 +185,7 @@ impl FnCallHashes {
     #[inline(always)]
     #[must_use]
     pub fn script(&self) -> u64 {
-        assert!(self.script.is_some());
+        debug_assert!(self.script.is_some());
         self.script.unwrap()
     }
 }
@@ -248,11 +248,7 @@ impl FnCallExpr {
     #[inline]
     #[must_use]
     pub fn constant_args(&self) -> bool {
-        if self.args.is_empty() {
+        self.args.is_empty() || self.args.iter().all(Expr::is_constant)
-            true
-        } else {
-            self.args.iter().all(Expr::is_constant)
-        }
     }
 }
 
@@ -383,7 +379,7 @@ impl fmt::Debug for Expr {
 
                 #[cfg(not(feature = "no_module"))]
                 if !x.1.is_empty() {
-                    write!(f, "{}{}", x.1, Token::DoubleColon.literal_syntax())?;
+                    write!(f, "{}{}", x.1, crate::engine::NAMESPACE_SEPARATOR)?;
                     let pos = x.1.position();
                     if !pos.is_none() {
                         display_pos = pos;

src/ast/namespace.rs

@@ -2,7 +2,6 @@
 #![cfg(not(feature = "no_module"))]
 
 use crate::ast::Ident;
-use crate::tokenizer::Token;
 use crate::{Position, StaticVec};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -46,7 +45,7 @@ impl fmt::Debug for Namespace {
                 .iter()
                 .map(Ident::as_str)
                 .collect::<StaticVec<_>>()
-                .join(Token::DoubleColon.literal_syntax()),
+                .join(crate::engine::NAMESPACE_SEPARATOR),
         )
     }
 }
@@ -63,7 +62,7 @@ impl fmt::Display for Namespace {
                 .iter()
                 .map(Ident::as_str)
                 .collect::<StaticVec<_>>()
-                .join(Token::DoubleColon.literal_syntax()),
+                .join(crate::engine::NAMESPACE_SEPARATOR),
         )
     }
 }

src/ast/script_fn.rs

@@ -34,7 +34,7 @@ pub struct ScriptFnDef {
     ///
     /// Each line in non-block doc-comments starts with `///`.
     #[cfg(feature = "metadata")]
-    pub comments: Box<[crate::Identifier]>,
+    pub comments: Box<[crate::SmartString]>,
 }
 
 impl fmt::Display for ScriptFnDef {

src/ast/stmt.rs

@@ -1,17 +1,18 @@
 //! Module defining script statements.
 
 use super::{ASTFlags, ASTNode, BinaryExpr, Expr, FnCallExpr, Ident};
-use crate::engine::KEYWORD_EVAL;
+use crate::engine::{KEYWORD_EVAL, OP_EQUALS};
+use crate::func::StraightHashMap;
 use crate::tokenizer::Token;
+use crate::types::dynamic::Union;
 use crate::types::Span;
-use crate::{calc_fn_hash, Position, StaticVec, INT};
+use crate::{calc_fn_hash, Dynamic, Position, StaticVec, INT};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
     borrow::Borrow,
-    collections::BTreeMap,
     fmt,
-    hash::Hash,
+    hash::{Hash, Hasher},
     mem,
     num::NonZeroUsize,
     ops::{Deref, DerefMut, Range, RangeInclusive},
@@ -29,8 +30,12 @@ pub struct OpAssignment {
     hash_op: u64,
     /// Op-assignment operator.
     op_assign: Token,
+    /// Syntax of op-assignment operator.
+    op_assign_syntax: &'static str,
     /// Underlying operator.
     op: Token,
+    /// Syntax of underlying operator.
+    op_syntax: &'static str,
     /// [Position] of the op-assignment operator.
     pos: Position,
 }
@@ -44,7 +49,9 @@ impl OpAssignment {
             hash_op_assign: 0,
             hash_op: 0,
             op_assign: Token::Equals,
+            op_assign_syntax: OP_EQUALS,
             op: Token::Equals,
+            op_syntax: OP_EQUALS,
             pos,
         }
     }
@@ -56,17 +63,28 @@ impl OpAssignment {
     }
     /// Get information if this [`OpAssignment`] is an op-assignment.
     ///
-    /// Returns `( hash_op_assign, hash_op, op_assign, op )`:
+    /// Returns `( hash_op_assign, hash_op, op_assign, op_assign_syntax, op, op_syntax )`:
     ///
     /// * `hash_op_assign`: Hash of the op-assignment call.
     /// * `hash_op`: Hash of the underlying operator call (for fallback).
     /// * `op_assign`: Op-assignment operator.
+    /// * `op_assign_syntax`: Syntax of op-assignment operator.
     /// * `op`: Underlying operator.
+    /// * `op_syntax`: Syntax of underlying operator.
     #[must_use]
     #[inline]
-    pub fn get_op_assignment_info(&self) -> Option<(u64, u64, &Token, &Token)> {
+    pub fn get_op_assignment_info(
+        &self,
+    ) -> Option<(u64, u64, &Token, &'static str, &Token, &'static str)> {
         if self.is_op_assignment() {
-            Some((self.hash_op_assign, self.hash_op, &self.op_assign, &self.op))
+            Some((
+                self.hash_op_assign,
+                self.hash_op,
+                &self.op_assign,
+                self.op_assign_syntax,
+                &self.op,
+                self.op_syntax,
+            ))
         } else {
             None
         }
@@ -99,11 +117,16 @@ impl OpAssignment {
             .get_base_op_from_assignment()
             .expect("op-assignment operator");
 
+        let op_assign_syntax = op_assign.literal_syntax();
+        let op_syntax = op.literal_syntax();
+
         Self {
-            hash_op_assign: calc_fn_hash(None, op_assign.literal_syntax(), 2),
+            hash_op_assign: calc_fn_hash(None, op_assign_syntax, 2),
-            hash_op: calc_fn_hash(None, op.literal_syntax(), 2),
+            hash_op: calc_fn_hash(None, op_syntax, 2),
             op_assign,
+            op_assign_syntax,
             op,
+            op_syntax,
             pos,
         }
     }
@@ -139,7 +162,9 @@ impl fmt::Debug for OpAssignment {
                 .field("hash_op_assign", &self.hash_op_assign)
                 .field("hash_op", &self.hash_op)
                 .field("op_assign", &self.op_assign)
+                .field("op_assign_syntax", &self.op_assign_syntax)
                 .field("op", &self.op)
+                .field("op_syntax", &self.op_syntax)
                 .field("pos", &self.pos)
                 .finish()
         } else {
@@ -233,7 +258,7 @@ impl IntoIterator for RangeCase {
     type Item = INT;
     type IntoIter = Box<dyn Iterator<Item = Self::Item>>;
 
-    #[inline(always)]
+    #[inline]
     #[must_use]
     fn into_iter(self) -> Self::IntoIter {
         match self {
@@ -245,7 +270,7 @@ impl IntoIterator for RangeCase {
 
 impl RangeCase {
     /// Returns `true` if the range contains no items.
-    #[inline(always)]
+    #[inline]
     #[must_use]
     pub fn is_empty(&self) -> bool {
         match self {
@@ -254,7 +279,7 @@ impl RangeCase {
         }
     }
     /// Size of the range.
-    #[inline(always)]
+    #[inline]
     #[must_use]
     pub fn len(&self) -> INT {
         match self {
@@ -264,15 +289,56 @@ impl RangeCase {
             Self::InclusiveInt(r, ..) => *r.end() - *r.start() + 1,
         }
     }
-    /// Is the specified number within this range?
+    /// Is the specified value within this range?
-    #[inline(always)]
+    #[inline]
     #[must_use]
-    pub fn contains(&self, n: INT) -> bool {
+    pub fn contains(&self, value: &Dynamic) -> bool {
+        match value {
+            Dynamic(Union::Int(v, ..)) => self.contains_int(*v),
+            #[cfg(not(feature = "no_float"))]
+            Dynamic(Union::Float(v, ..)) => self.contains_float(**v),
+            #[cfg(feature = "decimal")]
+            Dynamic(Union::Decimal(v, ..)) => self.contains_decimal(**v),
+            _ => false,
+        }
+    }
+    /// Is the specified number within this range?
+    #[inline]
+    #[must_use]
+    pub fn contains_int(&self, n: INT) -> bool {
         match self {
             Self::ExclusiveInt(r, ..) => r.contains(&n),
             Self::InclusiveInt(r, ..) => r.contains(&n),
         }
     }
+    /// Is the specified floating-point number within this range?
+    #[cfg(not(feature = "no_float"))]
+    #[inline]
+    #[must_use]
+    pub fn contains_float(&self, n: crate::FLOAT) -> bool {
+        use crate::FLOAT;
+
+        match self {
+            Self::ExclusiveInt(r, ..) => ((r.start as FLOAT)..(r.end as FLOAT)).contains(&n),
+            Self::InclusiveInt(r, ..) => ((*r.start() as FLOAT)..=(*r.end() as FLOAT)).contains(&n),
+        }
+    }
+    /// Is the specified decimal number within this range?
+    #[cfg(feature = "decimal")]
+    #[inline]
+    #[must_use]
+    pub fn contains_decimal(&self, n: rust_decimal::Decimal) -> bool {
+        use rust_decimal::Decimal;
+
+        match self {
+            Self::ExclusiveInt(r, ..) => {
+                (Into::<Decimal>::into(r.start)..Into::<Decimal>::into(r.end)).contains(&n)
+            }
+            Self::InclusiveInt(r, ..) => {
+                (Into::<Decimal>::into(*r.start())..=Into::<Decimal>::into(*r.end())).contains(&n)
+            }
+        }
+    }
     /// Is the specified range inclusive?
     #[inline(always)]
     #[must_use]
@@ -303,18 +369,31 @@ pub type CaseBlocksList = smallvec::SmallVec<[usize; 1]>;
 
 /// _(internals)_ A type containing all cases for a `switch` statement.
 /// Exported under the `internals` feature only.
-#[derive(Debug, Clone, Hash)]
+#[derive(Debug, Clone)]
 pub struct SwitchCasesCollection {
     /// List of [`ConditionalExpr`]'s.
     pub expressions: StaticVec<ConditionalExpr>,
     /// Dictionary mapping value hashes to [`ConditionalExpr`]'s.
-    pub cases: BTreeMap<u64, CaseBlocksList>,
+    pub cases: StraightHashMap<CaseBlocksList>,
     /// List of range cases.
     pub ranges: StaticVec<RangeCase>,
     /// Statements block for the default case (there can be no condition for the default case).
     pub def_case: Option<usize>,
 }
 
+impl Hash for SwitchCasesCollection {
+    #[inline(always)]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.expressions.hash(state);
+
+        self.cases.len().hash(state);
+        self.cases.iter().for_each(|kv| kv.hash(state));
+
+        self.ranges.hash(state);
+        self.def_case.hash(state);
+    }
+}
+
 /// Number of items to keep inline for [`StmtBlockContainer`].
 #[cfg(not(feature = "no_std"))]
 const STMT_BLOCK_INLINE_SIZE: usize = 8;

src/bin/rhai-repl.rs

@@ -2,7 +2,8 @@ use rhai::plugin::*;
 use rhai::{Dynamic, Engine, EvalAltResult, Module, Scope, AST, INT};
 use rustyline::config::Builder;
 use rustyline::error::ReadlineError;
-use rustyline::{Cmd, Editor, Event, EventHandler, KeyCode, KeyEvent, Modifiers, Movement};
+use rustyline::history::{History, SearchDirection};
+use rustyline::{Cmd, DefaultEditor, Event, EventHandler, KeyCode, KeyEvent, Modifiers, Movement};
 
 use std::{env, fs::File, io::Read, path::Path, process::exit};
 
@@ -188,14 +189,14 @@ fn load_script_files(engine: &mut Engine) {
 }
 
 // Setup the Rustyline editor.
-fn setup_editor() -> Editor<()> {
+fn setup_editor() -> DefaultEditor {
     //env_logger::init();
     let config = Builder::new()
         .tab_stop(4)
         .indent_size(4)
         .bracketed_paste(true)
         .build();
-    let mut rl = Editor::<()>::with_config(config).unwrap();
+    let mut rl = DefaultEditor::with_config(config).unwrap();
 
     // Bind more keys
 
@@ -336,7 +337,10 @@ fn main() {
     'main_loop: loop {
         if let Some(replace) = replacement.take() {
             input = replace;
-            if rl.add_history_entry(input.clone()) {
+            if rl
+                .add_history_entry(input.clone())
+                .expect("Failed to add history entry")
+            {
                 history_offset += 1;
             }
             if input.contains('\n') {
@@ -366,7 +370,9 @@ fn main() {
                         if !cmd.is_empty()
                             && !cmd.starts_with('!')
                             && cmd.trim() != "history"
-                            && rl.add_history_entry(input.clone())
+                            && rl
+                                .add_history_entry(input.clone())
+                                .expect("Failed to add history entry")
                         {
                             history_offset += 1;
                         }
@@ -476,7 +482,7 @@ fn main() {
 
                 let json = engine
                     .gen_fn_metadata_with_ast_to_json(&main_ast, false)
-                    .unwrap();
+                    .expect("Unable to generate JSON");
                 let mut f = std::fs::File::create("metadata.json")
                     .expect("Unable to create `metadata.json`");
                 f.write_all(json.as_bytes()).expect("Unable to write data");
@@ -484,7 +490,7 @@ fn main() {
                 continue;
             }
             "!!" => {
-                match rl.history().last() {
+                match rl.history().iter().last() {
                     Some(line) => {
                         replacement = Some(line.clone());
                         replacement_index = history_offset + rl.history().len() - 1;
@@ -514,8 +520,12 @@ fn main() {
             _ if cmd.starts_with('!') => {
                 if let Ok(num) = cmd[1..].parse::<usize>() {
                     if num >= history_offset {
-                        if let Some(line) = rl.history().get(num - history_offset) {
+                        if let Some(line) = rl
-                            replacement = Some(line.clone());
+                            .history()
+                            .get(num - history_offset, SearchDirection::Forward)
+                            .expect("Failed to get history entry")
+                        {
+                            replacement = Some(line.entry.into());
                             replacement_index = num;
                             continue;
                         }
@@ -578,7 +588,8 @@ fn main() {
         main_ast.clear_statements();
     }
 
-    rl.save_history(HISTORY_FILE).unwrap();
+    rl.save_history(HISTORY_FILE)
+        .expect("Failed to save history");
 
     println!("Bye!");
 }

src/engine.rs

@@ -5,13 +5,11 @@ use crate::func::native::{
     locked_write, OnDebugCallback, OnDefVarCallback, OnParseTokenCallback, OnPrintCallback,
     OnVarCallback,
 };
-use crate::module::ModuleFlags;
 use crate::packages::{Package, StandardPackage};
 use crate::tokenizer::Token;
 use crate::types::StringsInterner;
 use crate::{
-    Dynamic, Identifier, ImmutableString, Locked, Module, OptimizationLevel, SharedModule,
+    Dynamic, Identifier, ImmutableString, Locked, OptimizationLevel, SharedModule, StaticVec,
-    StaticVec,
 };
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -57,12 +55,19 @@ pub const OP_EQUALS: &str = Token::EqualsTo.literal_syntax();
 /// The `in` operator is implemented as a call to this function.
 pub const OP_CONTAINS: &str = "contains";
 
+/// Standard not operator.
+pub const OP_NOT: &str = Token::Bang.literal_syntax();
+
 /// Standard exclusive range operator.
 pub const OP_EXCLUSIVE_RANGE: &str = Token::ExclusiveRange.literal_syntax();
 
 /// Standard inclusive range operator.
 pub const OP_INCLUSIVE_RANGE: &str = Token::InclusiveRange.literal_syntax();
 
+/// Separator for namespaces.
+#[cfg(not(feature = "no_module"))]
+pub const NAMESPACE_SEPARATOR: &str = Token::DoubleColon.literal_syntax();
+
 /// Rhai main scripting engine.
 ///
 /// # Thread Safety
@@ -96,10 +101,10 @@ pub struct Engine {
 
     /// A module resolution service.
     #[cfg(not(feature = "no_module"))]
-    pub(crate) module_resolver: Box<dyn crate::ModuleResolver>,
+    pub(crate) module_resolver: Option<Box<dyn crate::ModuleResolver>>,
 
     /// Strings interner.
-    pub(crate) interned_strings: Locked<StringsInterner>,
+    pub(crate) interned_strings: Option<Box<Locked<StringsInterner>>>,
 
     /// A set of symbols to disable.
     pub(crate) disabled_symbols: Option<Box<BTreeSet<Identifier>>>,
@@ -110,7 +115,7 @@ pub struct Engine {
     /// Custom syntax.
     #[cfg(not(feature = "no_custom_syntax"))]
     pub(crate) custom_syntax: Option<
-        Box<std::collections::BTreeMap<Identifier, crate::api::custom_syntax::CustomSyntax>>,
+        Box<std::collections::BTreeMap<Identifier, Box<crate::api::custom_syntax::CustomSyntax>>>,
     >,
     /// Callback closure for filtering variable definition.
     pub(crate) def_var_filter: Option<Box<OnDefVarCallback>>,
@@ -120,9 +125,9 @@ pub struct Engine {
     pub(crate) token_mapper: Option<Box<OnParseTokenCallback>>,
 
     /// Callback closure for implementing the `print` command.
-    pub(crate) print: Box<OnPrintCallback>,
+    pub(crate) print: Option<Box<OnPrintCallback>>,
     /// Callback closure for implementing the `debug` command.
-    pub(crate) debug: Box<OnDebugCallback>,
+    pub(crate) debug: Option<Box<OnDebugCallback>>,
     /// Callback closure for progress reporting.
     #[cfg(not(feature = "unchecked"))]
     pub(crate) progress: Option<Box<crate::func::native::OnProgressCallback>>,
@@ -142,12 +147,10 @@ pub struct Engine {
 
     /// Callback closure for debugging.
     #[cfg(feature = "debugging")]
-    pub(crate) debugger_interface: Option<
+    pub(crate) debugger_interface: Option<(
-        Box<(
+        Box<crate::eval::OnDebuggingInit>,
-            Box<crate::eval::OnDebuggingInit>,
+        Box<crate::eval::OnDebuggerCallback>,
-            Box<crate::eval::OnDebuggerCallback>,
+    )>,
-        )>,
-    >,
 }
 
 impl fmt::Debug for Engine {
@@ -224,6 +227,49 @@ pub fn make_setter(id: &str) -> Identifier {
 }
 
 impl Engine {
+    /// An empty raw [`Engine`].
+    pub const RAW: Self = Self {
+        global_modules: StaticVec::new_const(),
+
+        #[cfg(not(feature = "no_module"))]
+        global_sub_modules: None,
+
+        #[cfg(not(feature = "no_module"))]
+        module_resolver: None,
+
+        interned_strings: None,
+        disabled_symbols: None,
+        #[cfg(not(feature = "no_custom_syntax"))]
+        custom_keywords: None,
+        #[cfg(not(feature = "no_custom_syntax"))]
+        custom_syntax: None,
+
+        def_var_filter: None,
+        resolve_var: None,
+        token_mapper: None,
+
+        print: None,
+        debug: None,
+
+        #[cfg(not(feature = "unchecked"))]
+        progress: None,
+
+        options: LangOptions::new(),
+
+        def_tag: Dynamic::UNIT,
+
+        #[cfg(not(feature = "no_optimize"))]
+        optimization_level: OptimizationLevel::Simple,
+        #[cfg(feature = "no_optimize")]
+        optimization_level: (),
+
+        #[cfg(not(feature = "unchecked"))]
+        limits: crate::api::limits::Limits::new(),
+
+        #[cfg(feature = "debugging")]
+        debugger_interface: None,
+    };
+
     /// Create a new [`Engine`].
     #[inline]
     #[must_use]
@@ -235,22 +281,25 @@ impl Engine {
         #[cfg(not(feature = "no_std"))]
         #[cfg(not(target_family = "wasm"))]
         {
-            engine.module_resolver = Box::new(crate::module::resolvers::FileModuleResolver::new());
+            engine.module_resolver =
+                Some(Box::new(crate::module::resolvers::FileModuleResolver::new()));
         }
 
+        engine.interned_strings = Some(Locked::new(StringsInterner::new()).into());
+
         // default print/debug implementations
         #[cfg(not(feature = "no_std"))]
         #[cfg(not(target_family = "wasm"))]
         {
-            engine.print = Box::new(|s| println!("{s}"));
+            engine.print = Some(Box::new(|s| println!("{s}")));
-            engine.debug = Box::new(|s, source, pos| match (source, pos) {
+            engine.debug = Some(Box::new(|s, source, pos| match (source, pos) {
                 (Some(source), crate::Position::NONE) => println!("{source} | {s}"),
                 #[cfg(not(feature = "no_position"))]
                 (Some(source), pos) => println!("{source} @ {pos:?} | {s}"),
                 (None, crate::Position::NONE) => println!("{s}"),
                 #[cfg(not(feature = "no_position"))]
                 (None, pos) => println!("{pos:?} | {s}"),
-            });
+            }));
         }
 
         engine.register_global_module(StandardPackage::new().as_shared_module());
@@ -259,59 +308,15 @@ impl Engine {
     }
 
     /// Create a new [`Engine`] with minimal built-in functions.
+    /// It returns a copy of [`Engine::RAW`].
+    ///
+    /// This is useful for creating a custom scripting engine with only the functions you need.
     ///
     /// Use [`register_global_module`][Engine::register_global_module] to add packages of functions.
     #[inline]
     #[must_use]
-    pub fn new_raw() -> Self {
+    pub const fn new_raw() -> Self {
-        let mut engine = Self {
+        Self::RAW
-            global_modules: StaticVec::new_const(),
-
-            #[cfg(not(feature = "no_module"))]
-            global_sub_modules: None,
-
-            #[cfg(not(feature = "no_module"))]
-            module_resolver: Box::new(crate::module::resolvers::DummyModuleResolver::new()),
-
-            interned_strings: StringsInterner::new().into(),
-            disabled_symbols: None,
-            #[cfg(not(feature = "no_custom_syntax"))]
-            custom_keywords: None,
-            #[cfg(not(feature = "no_custom_syntax"))]
-            custom_syntax: None,
-
-            def_var_filter: None,
-            resolve_var: None,
-            token_mapper: None,
-
-            print: Box::new(|_| {}),
-            debug: Box::new(|_, _, _| {}),
-
-            #[cfg(not(feature = "unchecked"))]
-            progress: None,
-
-            options: LangOptions::new(),
-
-            def_tag: Dynamic::UNIT,
-
-            #[cfg(not(feature = "no_optimize"))]
-            optimization_level: OptimizationLevel::Simple,
-            #[cfg(feature = "no_optimize")]
-            optimization_level: (),
-
-            #[cfg(not(feature = "unchecked"))]
-            limits: crate::api::limits::Limits::new(),
-
-            #[cfg(feature = "debugging")]
-            debugger_interface: None,
-        };
-
-        // Add the global namespace module
-        let mut global_namespace = Module::new();
-        global_namespace.flags |= ModuleFlags::INTERNAL;
-        engine.global_modules.push(global_namespace.into());
-
-        engine
     }
 
     /// Get an interned [string][ImmutableString].
@@ -322,7 +327,11 @@ impl Engine {
         &self,
         string: impl AsRef<str> + Into<ImmutableString>,
     ) -> ImmutableString {
-        locked_write(&self.interned_strings).get(string)
+        if let Some(ref interner) = self.interned_strings {
+            locked_write(interner).get(string)
+        } else {
+            string.into()
+        }
     }
 
     /// _(internals)_ Get an interned [string][ImmutableString].
@@ -331,13 +340,17 @@ impl Engine {
     /// [`Engine`] keeps a cache of [`ImmutableString`] instances and tries to avoid new allocations
     /// when an existing instance is found.
     #[cfg(feature = "internals")]
-    #[inline(always)]
+    #[inline]
     #[must_use]
     pub fn get_interned_string(
         &self,
         string: impl AsRef<str> + Into<ImmutableString>,
     ) -> ImmutableString {
-        locked_write(&self.interned_strings).get(string)
+        if let Some(ref interner) = self.interned_strings {
+            locked_write(interner).get(string)
+        } else {
+            string.into()
+        }
     }
 
     /// Get an empty [`ImmutableString`] which refers to a shared instance.
@@ -354,4 +367,17 @@ impl Engine {
     pub(crate) const fn is_debugger_registered(&self) -> bool {
         self.debugger_interface.is_some()
     }
+
+    /// Imitation of std::hints::black_box which requires nightly.
+    #[cfg(not(target_family = "wasm"))]
+    #[inline(never)]
+    pub(crate) fn black_box() -> usize {
+        unsafe { core::ptr::read_volatile(&0_usize as *const usize) }
+    }
+    /// Imitation of std::hints::black_box which requires nightly.
+    #[cfg(target_family = "wasm")]
+    #[inline(always)]
+    pub(crate) fn black_box() -> usize {
+        0
+    }
 }

src/eval/cache.rs

@@ -63,8 +63,8 @@ impl Caches {
     #[inline]
     #[must_use]
     pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
+        // Push a new function resolution cache if the stack is empty
         if self.0.is_empty() {
-            // Push a new function resolution cache if the stack is empty
             self.push_fn_resolution_cache();
         }
         self.0.last_mut().unwrap()

src/eval/chaining.rs

@@ -504,9 +504,7 @@ impl Engine {
                     global, caches, scope, this_ptr, expr, rhs, idx_values,
                 )?;
 
-                if !_arg_values.is_empty() {
+                idx_values.extend(_arg_values);
-                    idx_values.extend(_arg_values);
-                }
             }
 
             #[cfg(not(feature = "no_object"))]

src/eval/data_check.rs

@@ -8,90 +8,91 @@ use std::borrow::Borrow;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
+/// Recursively calculate the sizes of an array.
+///
+/// Sizes returned are `(` [`Array`][crate::Array], [`Map`][crate::Map] and [`String`] `)`.
+///
+/// # Panics
+///
+/// Panics if any interior data is shared (should never happen).
+#[cfg(not(feature = "no_index"))]
+#[inline]
+pub fn calc_array_sizes(array: &crate::Array) -> (usize, usize, usize) {
+    let (mut ax, mut mx, mut sx) = (0, 0, 0);
+
+    for value in array {
+        ax += 1;
+
+        match value.0 {
+            Union::Array(ref a, ..) => {
+                let (a, m, s) = calc_array_sizes(a);
+                ax += a;
+                mx += m;
+                sx += s;
+            }
+            Union::Blob(ref a, ..) => ax += 1 + a.len(),
+            #[cfg(not(feature = "no_object"))]
+            Union::Map(ref m, ..) => {
+                let (a, m, s) = calc_map_sizes(m);
+                ax += a;
+                mx += m;
+                sx += s;
+            }
+            Union::Str(ref s, ..) => sx += s.len(),
+            #[cfg(not(feature = "no_closure"))]
+            Union::Shared(..) => {
+                unreachable!("shared values discovered within data")
+            }
+            _ => (),
+        }
+    }
+
+    (ax, mx, sx)
+}
+/// Recursively calculate the sizes of a map.
+///
+/// Sizes returned are `(` [`Array`][crate::Array], [`Map`][crate::Map] and [`String`] `)`.
+///
+/// # Panics
+///
+/// Panics if any interior data is shared (should never happen).
+#[cfg(not(feature = "no_object"))]
+#[inline]
+pub fn calc_map_sizes(map: &crate::Map) -> (usize, usize, usize) {
+    let (mut ax, mut mx, mut sx) = (0, 0, 0);
+
+    for value in map.values() {
+        mx += 1;
+
+        match value.0 {
+            #[cfg(not(feature = "no_index"))]
+            Union::Array(ref a, ..) => {
+                let (a, m, s) = calc_array_sizes(a);
+                ax += a;
+                mx += m;
+                sx += s;
+            }
+            #[cfg(not(feature = "no_index"))]
+            Union::Blob(ref a, ..) => ax += 1 + a.len(),
+            Union::Map(ref m, ..) => {
+                let (a, m, s) = calc_map_sizes(m);
+                ax += a;
+                mx += m;
+                sx += s;
+            }
+            Union::Str(ref s, ..) => sx += s.len(),
+            #[cfg(not(feature = "no_closure"))]
+            Union::Shared(..) => {
+                unreachable!("shared values discovered within data")
+            }
+            _ => (),
+        }
+    }
+
+    (ax, mx, sx)
+}
+
 impl Dynamic {
-    /// Recursively calculate the sizes of an array.
-    ///
-    /// Sizes returned are `(` [`Array`][crate::Array], [`Map`][crate::Map] and [`String`] `)`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if any interior data is shared (should never happen).
-    #[cfg(not(feature = "no_index"))]
-    #[inline]
-    pub(crate) fn calc_array_sizes(array: &crate::Array) -> (usize, usize, usize) {
-        let (mut ax, mut mx, mut sx) = (0, 0, 0);
-
-        for value in array {
-            ax += 1;
-
-            match value.0 {
-                Union::Array(ref a, ..) => {
-                    let (a, m, s) = Self::calc_array_sizes(a);
-                    ax += a;
-                    mx += m;
-                    sx += s;
-                }
-                Union::Blob(ref a, ..) => ax += 1 + a.len(),
-                #[cfg(not(feature = "no_object"))]
-                Union::Map(ref m, ..) => {
-                    let (a, m, s) = Self::calc_map_sizes(m);
-                    ax += a;
-                    mx += m;
-                    sx += s;
-                }
-                Union::Str(ref s, ..) => sx += s.len(),
-                #[cfg(not(feature = "no_closure"))]
-                Union::Shared(..) => {
-                    unreachable!("shared values discovered within data")
-                }
-                _ => (),
-            }
-        }
-
-        (ax, mx, sx)
-    }
-    /// Recursively calculate the sizes of a map.
-    ///
-    /// Sizes returned are `(` [`Array`][crate::Array], [`Map`][crate::Map] and [`String`] `)`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if any interior data is shared (should never happen).
-    #[cfg(not(feature = "no_object"))]
-    #[inline]
-    pub(crate) fn calc_map_sizes(map: &crate::Map) -> (usize, usize, usize) {
-        let (mut ax, mut mx, mut sx) = (0, 0, 0);
-
-        for value in map.values() {
-            mx += 1;
-
-            match value.0 {
-                #[cfg(not(feature = "no_index"))]
-                Union::Array(ref a, ..) => {
-                    let (a, m, s) = Self::calc_array_sizes(a);
-                    ax += a;
-                    mx += m;
-                    sx += s;
-                }
-                #[cfg(not(feature = "no_index"))]
-                Union::Blob(ref a, ..) => ax += 1 + a.len(),
-                Union::Map(ref m, ..) => {
-                    let (a, m, s) = Self::calc_map_sizes(m);
-                    ax += a;
-                    mx += m;
-                    sx += s;
-                }
-                Union::Str(ref s, ..) => sx += s.len(),
-                #[cfg(not(feature = "no_closure"))]
-                Union::Shared(..) => {
-                    unreachable!("shared values discovered within data")
-                }
-                _ => (),
-            }
-        }
-
-        (ax, mx, sx)
-    }
     /// Recursively calculate the sizes of a value.
     ///
     /// Sizes returned are `(` [`Array`][crate::Array], [`Map`][crate::Map] and [`String`] `)`.
@@ -103,11 +104,11 @@ impl Dynamic {
     pub(crate) fn calc_data_sizes(&self, _top: bool) -> (usize, usize, usize) {
         match self.0 {
             #[cfg(not(feature = "no_index"))]
-            Union::Array(ref arr, ..) => Self::calc_array_sizes(arr),
+            Union::Array(ref arr, ..) => calc_array_sizes(arr),
             #[cfg(not(feature = "no_index"))]
             Union::Blob(ref blob, ..) => (blob.len(), 0, 0),
             #[cfg(not(feature = "no_object"))]
-            Union::Map(ref map, ..) => Self::calc_map_sizes(map),
+            Union::Map(ref map, ..) => calc_map_sizes(map),
             Union::Str(ref s, ..) => (0, 0, s.len()),
             #[cfg(not(feature = "no_closure"))]
             Union::Shared(..) if _top => self.read_lock::<Self>().unwrap().calc_data_sizes(true),
@@ -190,6 +191,7 @@ impl Engine {
     }
 
     /// Check if the number of operations stay within limit.
+    #[inline(always)]
     pub(crate) fn track_operation(
         &self,
         global: &mut GlobalRuntimeState,
@@ -198,16 +200,16 @@ impl Engine {
         global.num_operations += 1;
 
         // Guard against too many operations
-        let max = self.max_operations();
+        if self.max_operations() > 0 && global.num_operations > self.max_operations() {
-
+            Err(ERR::ErrorTooManyOperations(pos).into())
-        if max > 0 && global.num_operations > max {
+        } else {
-            return Err(ERR::ErrorTooManyOperations(pos).into());
+            self.progress
+                .as_ref()
+                .and_then(|progress| {
+                    progress(global.num_operations)
+                        .map(|token| Err(ERR::ErrorTerminated(token, pos).into()))
+                })
+                .unwrap_or(Ok(()))
         }
-
-        // Report progress
-        self.progress
-            .as_ref()
-            .and_then(|p| p(global.num_operations))
-            .map_or(Ok(()), |token| Err(ERR::ErrorTerminated(token, pos).into()))
     }
 }

src/eval/debugger.rs

@@ -510,7 +510,7 @@ impl Engine {
             let src = global.source_raw().cloned();
             let src = src.as_ref().map(|s| s.as_str());
             let context = EvalContext::new(self, global, caches, scope, this_ptr);
-            let (.., ref on_debugger) = **x;
+            let (.., ref on_debugger) = *x;
 
             let command = on_debugger(context, event, node, src, node.position());
 

src/eval/expr.rs

@@ -20,7 +20,7 @@ impl Engine {
         global: &GlobalRuntimeState,
         namespace: &crate::ast::Namespace,
     ) -> Option<crate::SharedModule> {
-        assert!(!namespace.is_empty());
+        debug_assert!(!namespace.is_empty());
 
         let root = namespace.root();
 
@@ -74,7 +74,7 @@ impl Engine {
                     if let Some(module) = self.search_imports(global, ns) {
                         return module.get_qualified_var(*hash_var).map_or_else(
                             || {
-                                let sep = crate::tokenizer::Token::DoubleColon.literal_syntax();
+                                let sep = crate::engine::NAMESPACE_SEPARATOR;
 
                                 Err(ERR::ErrorVariableNotFound(
                                     format!("{ns}{sep}{var_name}"),
@@ -104,7 +104,7 @@ impl Engine {
                             }
                         }
 
-                        let sep = crate::tokenizer::Token::DoubleColon.literal_syntax();
+                        let sep = crate::engine::NAMESPACE_SEPARATOR;
 
                         return Err(ERR::ErrorVariableNotFound(
                             format!("{ns}{sep}{var_name}"),
@@ -239,29 +239,22 @@ impl Engine {
         // Coded this way for better branch prediction.
         // Popular branches are lifted out of the `match` statement into their own branches.
 
+        #[cfg(feature = "debugging")]
+        let reset =
+            self.run_debugger_with_reset(global, caches, scope, this_ptr.as_deref_mut(), expr)?;
+        #[cfg(feature = "debugging")]
+        auto_restore!(global if Some(reset) => move |g| g.debugger_mut().reset_status(reset));
+
+        self.track_operation(global, expr.position())?;
+
         // Function calls should account for a relatively larger portion of expressions because
         // binary operators are also function calls.
         if let Expr::FnCall(x, pos) = expr {
-            #[cfg(feature = "debugging")]
-            let reset =
-                self.run_debugger_with_reset(global, caches, scope, this_ptr.as_deref_mut(), expr)?;
-            #[cfg(feature = "debugging")]
-            auto_restore!(global if Some(reset) => move |g| g.debugger_mut().reset_status(reset));
-
-            self.track_operation(global, expr.position())?;
-
             return self.eval_fn_call_expr(global, caches, scope, this_ptr, x, *pos);
         }
 
         // Then variable access.
-        // We shouldn't do this for too many variants because, soon or later, the added comparisons
-        // will cost more than the mis-predicted `match` branch.
         if let Expr::Variable(x, index, var_pos) = expr {
-            #[cfg(feature = "debugging")]
-            self.run_debugger(global, caches, scope, this_ptr.as_deref_mut(), expr)?;
-
-            self.track_operation(global, expr.position())?;
-
             return if index.is_none() && x.0.is_none() && x.3 == KEYWORD_THIS {
                 this_ptr
                     .ok_or_else(|| ERR::ErrorUnboundThis(*var_pos).into())
@@ -272,24 +265,26 @@ impl Engine {
             };
         }
 
-        #[cfg(feature = "debugging")]
+        // Then integer constants.
-        let reset =
+        if let Expr::IntegerConstant(x, ..) = expr {
-            self.run_debugger_with_reset(global, caches, scope, this_ptr.as_deref_mut(), expr)?;
+            return Ok((*x).into());
-        #[cfg(feature = "debugging")]
+        }
-        auto_restore!(global if Some(reset) => move |g| g.debugger_mut().reset_status(reset));
 
-        self.track_operation(global, expr.position())?;
+        // Stop merging branches here!
+        // We shouldn't lift out too many variants because, soon or later, the added comparisons
+        // will cost more than the mis-predicted `match` branch.
+        Self::black_box();
 
         match expr {
             // Constants
-            Expr::DynamicConstant(x, ..) => Ok(x.as_ref().clone()),
+            Expr::IntegerConstant(..) => unreachable!(),
-            Expr::IntegerConstant(x, ..) => Ok((*x).into()),
+            Expr::StringConstant(x, ..) => Ok(x.clone().into()),
+            Expr::BoolConstant(x, ..) => Ok((*x).into()),
             #[cfg(not(feature = "no_float"))]
             Expr::FloatConstant(x, ..) => Ok((*x).into()),
-            Expr::StringConstant(x, ..) => Ok(x.clone().into()),
             Expr::CharConstant(x, ..) => Ok((*x).into()),
-            Expr::BoolConstant(x, ..) => Ok((*x).into()),
             Expr::Unit(..) => Ok(Dynamic::UNIT),
+            Expr::DynamicConstant(x, ..) => Ok(x.as_ref().clone()),
 
             // `... ${...} ...`
             Expr::InterpolatedString(x, _) => {
@@ -434,8 +429,13 @@ impl Engine {
                     .and_then(|r| self.check_data_size(r, expr.start_position()))
             }
 
-            Expr::Stmt(x) if x.is_empty() => Ok(Dynamic::UNIT),
+            Expr::Stmt(x) => {
-            Expr::Stmt(x) => self.eval_stmt_block(global, caches, scope, this_ptr, x, true),
+                if x.is_empty() {
+                    Ok(Dynamic::UNIT)
+                } else {
+                    self.eval_stmt_block(global, caches, scope, this_ptr, x, true)
+                }
+            }
 
             #[cfg(not(feature = "no_index"))]
             Expr::Index(..) => {

src/eval/global_state.rs

@@ -127,20 +127,6 @@ impl GlobalRuntimeState {
     pub fn get_shared_import(&self, index: usize) -> Option<crate::SharedModule> {
         self.modules.as_ref().and_then(|m| m.get(index).cloned())
     }
-    /// Get a mutable reference to the globally-imported [module][crate::Module] at a
-    /// particular index.
-    ///
-    /// Not available under `no_module`.
-    #[cfg(not(feature = "no_module"))]
-    #[allow(dead_code)]
-    #[inline]
-    #[must_use]
-    pub(crate) fn get_shared_import_mut(
-        &mut self,
-        index: usize,
-    ) -> Option<&mut crate::SharedModule> {
-        self.modules.as_deref_mut().and_then(|m| m.get_mut(index))
-    }
     /// Get the index of a globally-imported [module][crate::Module] by name.
     ///
     /// Not available under `no_module`.

src/eval/mod.rs

@@ -11,6 +11,12 @@ mod target;
 pub use cache::{Caches, FnResolutionCache, FnResolutionCacheEntry};
 #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
 pub use chaining::ChainType;
+#[cfg(not(feature = "unchecked"))]
+#[cfg(not(feature = "no_index"))]
+pub use data_check::calc_array_sizes;
+#[cfg(not(feature = "unchecked"))]
+#[cfg(not(feature = "no_object"))]
+pub use data_check::calc_map_sizes;
 #[cfg(feature = "debugging")]
 pub use debugger::{
     BreakPoint, CallStackFrame, Debugger, DebuggerCommand, DebuggerEvent, DebuggerStatus,

src/eval/stmt.rs

@@ -3,9 +3,11 @@
 use super::{Caches, EvalContext, GlobalRuntimeState, Target};
 use crate::api::events::VarDefInfo;
 use crate::ast::{
-    ASTFlags, BinaryExpr, Expr, FlowControl, OpAssignment, Stmt, SwitchCasesCollection,
+    ASTFlags, BinaryExpr, ConditionalExpr, Expr, FlowControl, OpAssignment, Stmt,
+    SwitchCasesCollection,
 };
 use crate::func::{get_builtin_op_assignment_fn, get_hasher};
+use crate::tokenizer::Token;
 use crate::types::dynamic::{AccessMode, Union};
 use crate::{Dynamic, Engine, RhaiResult, RhaiResultOf, Scope, ERR, INT};
 use std::hash::{Hash, Hasher};
@@ -127,48 +129,119 @@ impl Engine {
 
         let pos = op_info.position();
 
-        if let Some((hash1, hash2, op_assign, op)) = op_info.get_op_assignment_info() {
+        if let Some((hash_x, hash, op_x, op_x_str, op, op_str)) = op_info.get_op_assignment_info() {
             let mut lock_guard = target.write_lock::<Dynamic>().unwrap();
-            let args = &mut [&mut *lock_guard, &mut new_val];
+            let mut done = false;
 
+            // Short-circuit built-in op-assignments if under Fast Operators mode
             if self.fast_operators() {
-                if let Some((func, need_context)) =
+                #[allow(clippy::wildcard_imports)]
-                    get_builtin_op_assignment_fn(op_assign, args[0], args[1])
+                use Token::*;
-                {
-                    // Built-in found
-                    auto_restore! { let orig_level = global.level; global.level += 1 }
 
-                    let context = if need_context {
+                done = true;
-                        let op = op_assign.literal_syntax();
+
-                        let source = global.source();
+                // For extremely simple primary data operations, do it directly
-                        Some((self, op, source, &*global, pos).into())
+                // to avoid the overhead of calling a function.
-                    } else {
+                match (&mut lock_guard.0, &mut new_val.0) {
-                        None
+                    (Union::Bool(b1, ..), Union::Bool(b2, ..)) => match op_x {
-                    };
+                        AndAssign => *b1 = *b1 && *b2,
-                    return func(context, args).map(|_| ());
+                        OrAssign => *b1 = *b1 || *b2,
+                        XOrAssign => *b1 = *b1 ^ *b2,
+                        _ => done = false,
+                    },
+                    (Union::Int(n1, ..), Union::Int(n2, ..)) => {
+                        #[cfg(not(feature = "unchecked"))]
+                        #[allow(clippy::wildcard_imports)]
+                        use crate::packages::arithmetic::arith_basic::INT::functions::*;
+
+                        #[cfg(not(feature = "unchecked"))]
+                        match op_x {
+                            PlusAssign => {
+                                *n1 = add(*n1, *n2).map_err(|err| err.fill_position(pos))?
+                            }
+                            MinusAssign => {
+                                *n1 = subtract(*n1, *n2).map_err(|err| err.fill_position(pos))?
+                            }
+                            MultiplyAssign => {
+                                *n1 = multiply(*n1, *n2).map_err(|err| err.fill_position(pos))?
+                            }
+                            DivideAssign => {
+                                *n1 = divide(*n1, *n2).map_err(|err| err.fill_position(pos))?
+                            }
+                            ModuloAssign => {
+                                *n1 = modulo(*n1, *n2).map_err(|err| err.fill_position(pos))?
+                            }
+                            _ => done = false,
+                        }
+                        #[cfg(feature = "unchecked")]
+                        match op_x {
+                            PlusAssign => *n1 += *n2,
+                            MinusAssign => *n1 -= *n2,
+                            MultiplyAssign => *n1 *= *n2,
+                            DivideAssign => *n1 /= *n2,
+                            ModuloAssign => *n1 %= *n2,
+                            _ => done = false,
+                        }
+                    }
+                    #[cfg(not(feature = "no_float"))]
+                    (Union::Float(f1, ..), Union::Float(f2, ..)) => match op_x {
+                        PlusAssign => **f1 += **f2,
+                        MinusAssign => **f1 -= **f2,
+                        MultiplyAssign => **f1 *= **f2,
+                        DivideAssign => **f1 /= **f2,
+                        ModuloAssign => **f1 %= **f2,
+                        _ => done = false,
+                    },
+                    #[cfg(not(feature = "no_float"))]
+                    (Union::Float(f1, ..), Union::Int(n2, ..)) => match op_x {
+                        PlusAssign => **f1 += *n2 as crate::FLOAT,
+                        MinusAssign => **f1 -= *n2 as crate::FLOAT,
+                        MultiplyAssign => **f1 *= *n2 as crate::FLOAT,
+                        DivideAssign => **f1 /= *n2 as crate::FLOAT,
+                        ModuloAssign => **f1 %= *n2 as crate::FLOAT,
+                        _ => done = false,
+                    },
+                    _ => done = false,
+                }
+
+                if !done {
+                    if let Some((func, need_context)) =
+                        get_builtin_op_assignment_fn(op_x, &*lock_guard, &new_val)
+                    {
+                        // We may not need to bump the level because built-in's do not need it.
+                        //auto_restore! { let orig_level = global.level; global.level += 1 }
+
+                        let args = &mut [&mut *lock_guard, &mut new_val];
+                        let context = need_context
+                            .then(|| (self, op_x_str, global.source(), &*global, pos).into());
+                        let _ = func(context, args).map_err(|err| err.fill_position(pos))?;
+                        done = true;
+                    }
                 }
             }
 
-            let token = Some(op_assign);
+            if !done {
-            let op_assign = op_assign.literal_syntax();
+                let opx = Some(op_x);
+                let args = &mut [&mut *lock_guard, &mut new_val];
 
-            match self.exec_native_fn_call(global, caches, op_assign, token, hash1, args, true, pos)
+                match self
-            {
+                    .exec_native_fn_call(global, caches, op_x_str, opx, hash_x, args, true, pos)
-                Ok(_) => (),
-                Err(err) if matches!(*err, ERR::ErrorFunctionNotFound(ref f, ..) if f.starts_with(op_assign)) =>
                 {
-                    // Expand to `var = var op rhs`
+                    Ok(_) => (),
-                    let token = Some(op);
+                    Err(err) if matches!(*err, ERR::ErrorFunctionNotFound(ref f, ..) if f.starts_with(op_x_str)) =>
-                    let op = op.literal_syntax();
+                    {
+                        // Expand to `var = var op rhs`
+                        let op = Some(op);
 
-                    *args[0] = self
+                        *args[0] = self
-                        .exec_native_fn_call(global, caches, op, token, hash2, args, true, pos)?
+                            .exec_native_fn_call(global, caches, op_str, op, hash, args, true, pos)?
-                        .0;
+                            .0;
+                    }
+                    Err(err) => return Err(err),
                 }
-                Err(err) => return Err(err),
-            }
 
-            self.check_data_size(&*args[0], root.position())?;
+                self.check_data_size(&*args[0], root.position())?;
+            }
         } else {
             // Normal assignment
             match target {
@@ -200,24 +273,20 @@ impl Engine {
         #[cfg(feature = "debugging")]
         auto_restore!(global if Some(reset) => move |g| g.debugger_mut().reset_status(reset));
 
+        self.track_operation(global, stmt.position())?;
+
         // Coded this way for better branch prediction.
         // Popular branches are lifted out of the `match` statement into their own branches.
 
         // Function calls should account for a relatively larger portion of statements.
         if let Stmt::FnCall(x, pos) = stmt {
-            self.track_operation(global, stmt.position())?;
-
             return self.eval_fn_call_expr(global, caches, scope, this_ptr, x, *pos);
         }
 
         // Then assignments.
-        // We shouldn't do this for too many variants because, soon or later, the added comparisons
-        // will cost more than the mis-predicted `match` branch.
         if let Stmt::Assignment(x, ..) = stmt {
             let (op_info, BinaryExpr { lhs, rhs }) = &**x;
 
-            self.track_operation(global, stmt.position())?;
-
             if let Expr::Variable(x, ..) = lhs {
                 let rhs_val = self
                     .eval_expr(global, caches, scope, this_ptr.as_deref_mut(), rhs)?
@@ -281,7 +350,97 @@ impl Engine {
             }
         }
 
-        self.track_operation(global, stmt.position())?;
+        // Then variable definitions.
+        if let Stmt::Var(x, options, pos) = stmt {
+            if !self.allow_shadowing() && scope.contains(&x.0) {
+                return Err(ERR::ErrorVariableExists(x.0.to_string(), *pos).into());
+            }
+
+            // Let/const statement
+            let (var_name, expr, index) = &**x;
+
+            let access = if options.contains(ASTFlags::CONSTANT) {
+                AccessMode::ReadOnly
+            } else {
+                AccessMode::ReadWrite
+            };
+            let export = options.contains(ASTFlags::EXPORTED);
+
+            // Check variable definition filter
+            if let Some(ref filter) = self.def_var_filter {
+                let will_shadow = scope.contains(var_name);
+                let is_const = access == AccessMode::ReadOnly;
+                let info = VarDefInfo {
+                    name: var_name,
+                    is_const,
+                    nesting_level: global.scope_level,
+                    will_shadow,
+                };
+                let orig_scope_len = scope.len();
+                let context =
+                    EvalContext::new(self, global, caches, scope, this_ptr.as_deref_mut());
+                let filter_result = filter(true, info, context);
+
+                if orig_scope_len != scope.len() {
+                    // The scope is changed, always search from now on
+                    global.always_search_scope = true;
+                }
+
+                if !filter_result? {
+                    return Err(ERR::ErrorForbiddenVariable(var_name.to_string(), *pos).into());
+                }
+            }
+
+            // Evaluate initial value
+            let mut value = self
+                .eval_expr(global, caches, scope, this_ptr, expr)?
+                .flatten()
+                .intern_string(self);
+
+            let _alias = if !rewind_scope {
+                // Put global constants into global module
+                #[cfg(not(feature = "no_function"))]
+                #[cfg(not(feature = "no_module"))]
+                if global.scope_level == 0
+                    && access == AccessMode::ReadOnly
+                    && global.lib.iter().any(|m| !m.is_empty())
+                {
+                    crate::func::locked_write(global.constants.get_or_insert_with(|| {
+                        crate::Shared::new(crate::Locked::new(std::collections::BTreeMap::new()))
+                    }))
+                    .insert(var_name.name.clone(), value.clone());
+                }
+
+                if export {
+                    Some(var_name)
+                } else {
+                    None
+                }
+            } else if export {
+                unreachable!("exported variable not on global level");
+            } else {
+                None
+            };
+
+            if let Some(index) = index {
+                value.set_access_mode(access);
+                *scope.get_mut_by_index(scope.len() - index.get()) = value;
+            } else {
+                scope.push_entry(var_name.name.clone(), access, value);
+            }
+
+            #[cfg(not(feature = "no_module"))]
+            if let Some(alias) = _alias {
+                scope.add_alias_by_index(scope.len() - 1, alias.as_str().into());
+            }
+
+            return Ok(Dynamic::UNIT);
+        }
+
+        // Stop merging branches here!
+        // We shouldn't lift out too many variants because, soon or later, the added comparisons
+        // will cost more than the mis-predicted `match` branch.
+        Self::black_box();
 
         match stmt {
             // No-op
@@ -293,9 +452,12 @@ impl Engine {
                 .map(Dynamic::flatten),
 
             // Block scope
-            Stmt::Block(statements, ..) if statements.is_empty() => Ok(Dynamic::UNIT),
             Stmt::Block(statements, ..) => {
-                self.eval_stmt_block(global, caches, scope, this_ptr, statements, true)
+                if statements.is_empty() {
+                    Ok(Dynamic::UNIT)
+                } else {
+                    self.eval_stmt_block(global, caches, scope, this_ptr, statements, true)
+                }
             }
 
             // If statement
@@ -311,12 +473,14 @@ impl Engine {
                     .as_bool()
                     .map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
 
-                if guard_val && !if_block.is_empty() {
+                match guard_val {
-                    self.eval_stmt_block(global, caches, scope, this_ptr, if_block, true)
+                    true if !if_block.is_empty() => {
-                } else if !guard_val && !else_block.is_empty() {
+                        self.eval_stmt_block(global, caches, scope, this_ptr, if_block, true)
-                    self.eval_stmt_block(global, caches, scope, this_ptr, else_block, true)
+                    }
-                } else {
+                    false if !else_block.is_empty() => {
-                    Ok(Dynamic::UNIT)
+                        self.eval_stmt_block(global, caches, scope, this_ptr, else_block, true)
+                    }
+                    _ => Ok(Dynamic::UNIT),
                 }
             }
 
@@ -343,7 +507,7 @@ impl Engine {
 
                     // First check hashes
                     if let Some(case_blocks_list) = cases.get(&hash) {
-                        assert!(!case_blocks_list.is_empty());
+                        debug_assert!(!case_blocks_list.is_empty());
 
                         for &index in case_blocks_list {
                             let block = &expressions[index];
@@ -363,15 +527,13 @@ impl Engine {
                                 break;
                             }
                         }
-                    } else if value.is_int() && !ranges.is_empty() {
+                    } else if !ranges.is_empty() {
                         // Then check integer ranges
-                        let value = value.as_int().expect("`INT`");
+                        for r in ranges.iter().filter(|r| r.contains(&value)) {
+                            let ConditionalExpr { condition, expr } = &expressions[r.index()];
 
-                        for r in ranges.iter().filter(|r| r.contains(value)) {
+                            let cond_result = match condition {
-                            let block = &expressions[r.index()];
+                                Expr::BoolConstant(b, ..) => *b,
-
-                            let cond_result = match block.condition {
-                                Expr::BoolConstant(b, ..) => b,
                                 ref c => self
                                     .eval_expr(global, caches, scope, this_ptr.as_deref_mut(), c)?
                                     .as_bool()
@@ -381,7 +543,7 @@ impl Engine {
                             };
 
                             if cond_result {
-                                result = Some(&block.expr);
+                                result = Some(expr);
                                 break;
                             }
                         }
@@ -521,12 +683,10 @@ impl Engine {
                 auto_restore! { scope => rewind; let orig_scope_len = scope.len(); }
 
                 // Add the loop variables
-                let counter_index = if counter.is_empty() {
+                let counter_index = (!counter.is_empty()).then(|| {
-                    usize::MAX
-                } else {
                     scope.push(counter.name.clone(), 0 as INT);
                     scope.len() - 1
-                };
+                });
 
                 scope.push(var_name.name.clone(), ());
                 let index = scope.len() - 1;
@@ -535,7 +695,7 @@ impl Engine {
 
                 for (x, iter_value) in iter_func(iter_obj).enumerate() {
                     // Increment counter
-                    if counter_index < usize::MAX {
+                    if let Some(counter_index) = counter_index {
                         // As the variable increments from 0, this should always work
                         // since any overflow will first be caught below.
                         let index_value = x as INT;
@@ -695,94 +855,6 @@ impl Engine {
             // Empty return
             Stmt::Return(None, .., pos) => Err(ERR::Return(Dynamic::UNIT, *pos).into()),
 
-            // Let/const statement - shadowing disallowed
-            Stmt::Var(x, .., pos) if !self.allow_shadowing() && scope.contains(&x.0) => {
-                Err(ERR::ErrorVariableExists(x.0.to_string(), *pos).into())
-            }
-            // Let/const statement
-            Stmt::Var(x, options, pos) => {
-                let (var_name, expr, index) = &**x;
-
-                let access = if options.contains(ASTFlags::CONSTANT) {
-                    AccessMode::ReadOnly
-                } else {
-                    AccessMode::ReadWrite
-                };
-                let export = options.contains(ASTFlags::EXPORTED);
-
-                // Check variable definition filter
-                if let Some(ref filter) = self.def_var_filter {
-                    let will_shadow = scope.contains(var_name);
-                    let is_const = access == AccessMode::ReadOnly;
-                    let info = VarDefInfo {
-                        name: var_name,
-                        is_const,
-                        nesting_level: global.scope_level,
-                        will_shadow,
-                    };
-                    let orig_scope_len = scope.len();
-                    let context =
-                        EvalContext::new(self, global, caches, scope, this_ptr.as_deref_mut());
-                    let filter_result = filter(true, info, context);
-
-                    if orig_scope_len != scope.len() {
-                        // The scope is changed, always search from now on
-                        global.always_search_scope = true;
-                    }
-
-                    if !filter_result? {
-                        return Err(ERR::ErrorForbiddenVariable(var_name.to_string(), *pos).into());
-                    }
-                }
-
-                // Evaluate initial value
-                let mut value = self
-                    .eval_expr(global, caches, scope, this_ptr, expr)?
-                    .flatten()
-                    .intern_string(self);
-
-                let _alias = if !rewind_scope {
-                    // Put global constants into global module
-                    #[cfg(not(feature = "no_function"))]
-                    #[cfg(not(feature = "no_module"))]
-                    if global.scope_level == 0
-                        && access == AccessMode::ReadOnly
-                        && global.lib.iter().any(|m| !m.is_empty())
-                    {
-                        crate::func::locked_write(global.constants.get_or_insert_with(|| {
-                            crate::Shared::new(
-                                crate::Locked::new(std::collections::BTreeMap::new()),
-                            )
-                        }))
-                        .insert(var_name.name.clone(), value.clone());
-                    }
-
-                    if export {
-                        Some(var_name)
-                    } else {
-                        None
-                    }
-                } else if export {
-                    unreachable!("exported variable not on global level");
-                } else {
-                    None
-                };
-
-                if let Some(index) = index {
-                    value.set_access_mode(access);
-                    *scope.get_mut_by_index(scope.len() - index.get()) = value;
-                } else {
-                    scope.push_entry(var_name.name.clone(), access, value);
-                }
-
-                #[cfg(not(feature = "no_module"))]
-                if let Some(alias) = _alias {
-                    scope.add_alias_by_index(scope.len() - 1, alias.as_str().into());
-                }
-
-                Ok(Dynamic::UNIT)
-            }
-
             // Import statement
             #[cfg(not(feature = "no_module"))]
             Stmt::Import(x, _pos) => {
@@ -807,14 +879,16 @@ impl Engine {
 
                 let module = resolver
                     .as_ref()
-                    .and_then(|r| match r.resolve_raw(self, global, &path, path_pos) {
+                    .and_then(
-                        Err(err) if matches!(*err, ERR::ErrorModuleNotFound(..)) => None,
+                        |r| match r.resolve_raw(self, global, scope, &path, path_pos) {
-                        result => Some(result),
+                            Err(err) if matches!(*err, ERR::ErrorModuleNotFound(..)) => None,
-                    })
+                            result => Some(result),
+                        },
+                    )
                     .or_else(|| {
                         Some(
-                            self.module_resolver
+                            self.module_resolver()
-                                .resolve_raw(self, global, &path, path_pos),
+                                .resolve_raw(self, global, scope, &path, path_pos),
                         )
                     })
                     .unwrap_or_else(|| {

src/func/builtin.rs

@@ -27,48 +27,6 @@ use rust_decimal::Decimal;
 /// The `unchecked` feature is not active.
 const CHECKED_BUILD: bool = cfg!(not(feature = "unchecked"));
 
-/// Is the type a numeric type?
-#[inline]
-#[must_use]
-fn is_numeric(type_id: TypeId) -> bool {
-    if type_id == TypeId::of::<INT>() {
-        return true;
-    }
-
-    #[cfg(not(feature = "only_i64"))]
-    #[cfg(not(feature = "only_i32"))]
-    if type_id == TypeId::of::<u8>()
-        || type_id == TypeId::of::<u16>()
-        || type_id == TypeId::of::<u32>()
-        || type_id == TypeId::of::<u64>()
-        || type_id == TypeId::of::<i8>()
-        || type_id == TypeId::of::<i16>()
-        || type_id == TypeId::of::<i32>()
-        || type_id == TypeId::of::<i64>()
-    {
-        return true;
-    }
-
-    #[cfg(not(feature = "only_i64"))]
-    #[cfg(not(feature = "only_i32"))]
-    #[cfg(not(target_family = "wasm"))]
-    if type_id == TypeId::of::<u128>() || type_id == TypeId::of::<i128>() {
-        return true;
-    }
-
-    #[cfg(not(feature = "no_float"))]
-    if type_id == TypeId::of::<f32>() || type_id == TypeId::of::<f64>() {
-        return true;
-    }
-
-    #[cfg(feature = "decimal")]
-    if type_id == TypeId::of::<rust_decimal::Decimal>() {
-        return true;
-    }
-
-    false
-}
-
 /// A function that returns `true`.
 #[inline(always)]
 #[allow(clippy::unnecessary_wraps)]
@@ -584,22 +542,7 @@ pub fn get_builtin_binary_op_fn(op: &Token, x: &Dynamic, y: &Dynamic) -> Option<
 
     // One of the operands is a custom type, so it is never built-in
     if x.is_variant() || y.is_variant() {
-        return if is_numeric(type1) && is_numeric(type2) {
+        return None;
-            // Disallow comparisons between different numeric types
-            None
-        } else if type1 != type2 {
-            // If the types are not the same, default to not compare
-            match op {
-                NotEqualsTo => Some((const_true_fn, false)),
-                EqualsTo | GreaterThan | GreaterThanEqualsTo | LessThan | LessThanEqualsTo => {
-                    Some((const_false_fn, false))
-                }
-                _ => None,
-            }
-        } else {
-            // Disallow comparisons between the same type
-            None
-        };
     }
 
     // Default comparison operators for different types
@@ -741,6 +684,7 @@ pub fn get_builtin_op_assignment_fn(op: &Token, x: &Dynamic, y: &Dynamic) -> Opt
             return match op {
                 AndAssign => impl_op!(bool = x && as_bool),
                 OrAssign => impl_op!(bool = x || as_bool),
+                XOrAssign => impl_op!(bool = x ^ as_bool),
                 _ => None,
             };
         }

src/func/call.rs

@@ -9,6 +9,7 @@ use crate::engine::{
 };
 use crate::eval::{Caches, FnResolutionCacheEntry, GlobalRuntimeState};
 use crate::tokenizer::{is_valid_function_name, Token};
+use crate::types::dynamic::Union;
 use crate::{
     calc_fn_hash, calc_fn_hash_full, Dynamic, Engine, FnArgsVec, FnPtr, ImmutableString,
     OptimizationLevel, Position, RhaiResult, RhaiResultOf, Scope, Shared, ERR,
@@ -363,7 +364,7 @@ impl Engine {
         );
 
         if let Some(FnResolutionCacheEntry { func, source }) = func {
-            assert!(func.is_native());
+            debug_assert!(func.is_native());
 
             // Push a new call stack frame
             #[cfg(feature = "debugging")]
@@ -398,11 +399,9 @@ impl Engine {
             let is_method = func.is_method();
             let src = source.as_ref().map(|s| s.as_str());
 
-            let context = if func.has_context() {
+            let context = func
-                Some((self, name, src, &*global, pos).into())
+                .has_context()
-            } else {
+                .then(|| (self, name, src, &*global, pos).into());
-                None
-            };
 
             let mut _result = if let Some(f) = func.get_plugin_fn() {
                 if !f.is_pure() && !args.is_empty() && args[0].is_read_only() {
@@ -461,18 +460,26 @@ impl Engine {
             // See if the function match print/debug (which requires special processing)
             return Ok(match name {
                 KEYWORD_PRINT => {
-                    let text = result.into_immutable_string().map_err(|typ| {
+                    if let Some(ref print) = self.print {
-                        let t = self.map_type_name(type_name::<ImmutableString>()).into();
+                        let text = result.into_immutable_string().map_err(|typ| {
-                        ERR::ErrorMismatchOutputType(t, typ.into(), pos)
+                            let t = self.map_type_name(type_name::<ImmutableString>()).into();
-                    })?;
+                            ERR::ErrorMismatchOutputType(t, typ.into(), pos)
-                    ((*self.print)(&text).into(), false)
+                        })?;
+                        (print(&text).into(), false)
+                    } else {
+                        (Dynamic::UNIT, false)
+                    }
                 }
                 KEYWORD_DEBUG => {
-                    let text = result.into_immutable_string().map_err(|typ| {
+                    if let Some(ref debug) = self.debug {
-                        let t = self.map_type_name(type_name::<ImmutableString>()).into();
+                        let text = result.into_immutable_string().map_err(|typ| {
-                        ERR::ErrorMismatchOutputType(t, typ.into(), pos)
+                            let t = self.map_type_name(type_name::<ImmutableString>()).into();
-                    })?;
+                            ERR::ErrorMismatchOutputType(t, typ.into(), pos)
-                    ((*self.debug)(&text, global.source(), pos).into(), false)
+                        })?;
+                        (debug(&text, global.source(), pos).into(), false)
+                    } else {
+                        (Dynamic::UNIT, false)
+                    }
                 }
                 _ => (result, is_method),
             });
@@ -633,7 +640,7 @@ impl Engine {
                 .cloned()
             {
                 // Script function call
-                assert!(func.is_script());
+                debug_assert!(func.is_script());
 
                 let f = func.get_script_fn_def().expect("script-defined function");
                 let environ = func.get_encapsulated_environ();
@@ -810,7 +817,8 @@ impl Engine {
                 if call_args.is_empty() {
                     let typ = self.map_type_name(target.type_name());
                     return Err(self.make_type_mismatch_err::<FnPtr>(typ, fn_call_pos));
-                } else if !call_args[0].is_fnptr() {
+                }
+                if !call_args[0].is_fnptr() {
                     let typ = self.map_type_name(call_args[0].type_name());
                     return Err(self.make_type_mismatch_err::<FnPtr>(typ, first_arg_pos));
                 }
@@ -1251,9 +1259,7 @@ impl Engine {
         }
 
         // Call with blank scope
-        if total_args == 0 && curry.is_empty() {
+        if total_args > 0 || !curry.is_empty() {
-            // No arguments
-        } else {
             // If the first argument is a variable, and there is no curried arguments,
             // convert to method-call style in order to leverage potential &mut first argument and
             // avoid cloning the value
@@ -1324,9 +1330,7 @@ impl Engine {
         let args = &mut FnArgsVec::with_capacity(args_expr.len());
         let mut first_arg_value = None;
 
-        if args_expr.is_empty() {
+        if !args_expr.is_empty() {
-            // No arguments
-        } else {
             // See if the first argument is a variable (not namespace-qualified).
             // If so, convert to method-call style in order to leverage potential &mut first argument
             // and avoid cloning the value
@@ -1460,11 +1464,9 @@ impl Engine {
 
             Some(f) if f.is_plugin_fn() => {
                 let f = f.get_plugin_fn().expect("plugin function");
-                let context = if f.has_context() {
+                let context = f
-                    Some((self, fn_name, module.id(), &*global, pos).into())
+                    .has_context()
-                } else {
+                    .then(|| (self, fn_name, module.id(), &*global, pos).into());
-                    None
-                };
                 if !f.is_pure() && !args.is_empty() && args[0].is_read_only() {
                     Err(ERR::ErrorNonPureMethodCallOnConstant(fn_name.to_string(), pos).into())
                 } else {
@@ -1475,29 +1477,27 @@ impl Engine {
 
             Some(f) if f.is_native() => {
                 let func = f.get_native_fn().expect("native function");
-                let context = if f.has_context() {
+                let context = f
-                    Some((self, fn_name, module.id(), &*global, pos).into())
+                    .has_context()
-                } else {
+                    .then(|| (self, fn_name, module.id(), &*global, pos).into());
-                    None
-                };
                 func(context, args).and_then(|r| self.check_data_size(r, pos))
             }
 
             Some(f) => unreachable!("unknown function type: {:?}", f),
 
-            None => {
+            None => Err(ERR::ErrorFunctionNotFound(
-                let sig = if namespace.is_empty() {
+                if namespace.is_empty() {
                     self.gen_fn_call_signature(fn_name, args)
                 } else {
                     format!(
                         "{namespace}{}{}",
-                        crate::tokenizer::Token::DoubleColon.literal_syntax(),
+                        crate::engine::NAMESPACE_SEPARATOR,
                         self.gen_fn_call_signature(fn_name, args)
                     )
-                };
+                },
-
+                pos,
-                Err(ERR::ErrorFunctionNotFound(sig, pos).into())
+            )
-            }
+            .into()),
         }
     }
 
@@ -1547,6 +1547,9 @@ impl Engine {
     /// # Main Entry-Point (`FnCallExpr`)
     ///
     /// Evaluate a function call expression.
+    ///
+    /// This method tries to short-circuit function resolution under Fast Operators mode if the
+    /// function call is an operator.
     pub(crate) fn eval_fn_call_expr(
         &self,
         global: &mut GlobalRuntimeState,
@@ -1570,23 +1573,29 @@ impl Engine {
         let op_token = op_token.as_ref();
 
         // Short-circuit native unary operator call if under Fast Operators mode
-        if op_token == Some(&Token::Bang) && self.fast_operators() && args.len() == 1 {
+        if self.fast_operators() && args.len() == 1 && op_token == Some(&Token::Bang) {
             let mut value = self
                 .get_arg_value(global, caches, scope, this_ptr.as_deref_mut(), &args[0])?
                 .0
                 .flatten();
 
-            return value.as_bool().map(|r| (!r).into()).or_else(|_| {
+            return match value.0 {
-                let operand = &mut [&mut value];
+                Union::Bool(b, ..) => Ok((!b).into()),
-                self.exec_fn_call(
+                _ => {
-                    global, caches, None, name, op_token, *hashes, operand, false, false, pos,
+                    let operand = &mut [&mut value];
-                )
+                    self.exec_fn_call(
-                .map(|(v, ..)| v)
+                        global, caches, None, name, op_token, *hashes, operand, false, false, pos,
-            });
+                    )
+                    .map(|(v, ..)| v)
+                }
+            };
         }
 
         // Short-circuit native binary operator call if under Fast Operators mode
         if op_token.is_some() && self.fast_operators() && args.len() == 2 {
+            #[allow(clippy::wildcard_imports)]
+            use Token::*;
+
             let mut lhs = self
                 .get_arg_value(global, caches, scope, this_ptr.as_deref_mut(), &args[0])?
                 .0
@@ -1597,19 +1606,128 @@ impl Engine {
                 .0
                 .flatten();
 
+            // For extremely simple primary data operations, do it directly
+            // to avoid the overhead of calling a function.
+            match (&lhs.0, &rhs.0) {
+                (Union::Unit(..), Union::Unit(..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok(Dynamic::TRUE),
+                    NotEqualsTo | GreaterThan | GreaterThanEqualsTo | LessThan
+                    | LessThanEqualsTo => return Ok(Dynamic::FALSE),
+                    _ => (),
+                },
+                (Union::Bool(b1, ..), Union::Bool(b2, ..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok((*b1 == *b2).into()),
+                    NotEqualsTo => return Ok((*b1 != *b2).into()),
+                    GreaterThan | GreaterThanEqualsTo | LessThan | LessThanEqualsTo => {
+                        return Ok(Dynamic::FALSE)
+                    }
+                    Pipe => return Ok((*b1 || *b2).into()),
+                    Ampersand => return Ok((*b1 && *b2).into()),
+                    _ => (),
+                },
+                (Union::Int(n1, ..), Union::Int(n2, ..)) => {
+                    #[cfg(not(feature = "unchecked"))]
+                    #[allow(clippy::wildcard_imports)]
+                    use crate::packages::arithmetic::arith_basic::INT::functions::*;
+
+                    #[cfg(not(feature = "unchecked"))]
+                    match op_token.unwrap() {
+                        EqualsTo => return Ok((*n1 == *n2).into()),
+                        NotEqualsTo => return Ok((*n1 != *n2).into()),
+                        GreaterThan => return Ok((*n1 > *n2).into()),
+                        GreaterThanEqualsTo => return Ok((*n1 >= *n2).into()),
+                        LessThan => return Ok((*n1 < *n2).into()),
+                        LessThanEqualsTo => return Ok((*n1 <= *n2).into()),
+                        Plus => return add(*n1, *n2).map(Into::into),
+                        Minus => return subtract(*n1, *n2).map(Into::into),
+                        Multiply => return multiply(*n1, *n2).map(Into::into),
+                        Divide => return divide(*n1, *n2).map(Into::into),
+                        Modulo => return modulo(*n1, *n2).map(Into::into),
+                        _ => (),
+                    }
+                    #[cfg(feature = "unchecked")]
+                    match op_token.unwrap() {
+                        EqualsTo => return Ok((*n1 == *n2).into()),
+                        NotEqualsTo => return Ok((*n1 != *n2).into()),
+                        GreaterThan => return Ok((*n1 > *n2).into()),
+                        GreaterThanEqualsTo => return Ok((*n1 >= *n2).into()),
+                        LessThan => return Ok((*n1 < *n2).into()),
+                        LessThanEqualsTo => return Ok((*n1 <= *n2).into()),
+                        Plus => return Ok((*n1 + *n2).into()),
+                        Minus => return Ok((*n1 - *n2).into()),
+                        Multiply => return Ok((*n1 * *n2).into()),
+                        Divide => return Ok((*n1 / *n2).into()),
+                        Modulo => return Ok((*n1 % *n2).into()),
+                        _ => (),
+                    }
+                }
+                #[cfg(not(feature = "no_float"))]
+                (Union::Float(f1, ..), Union::Float(f2, ..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok((**f1 == **f2).into()),
+                    NotEqualsTo => return Ok((**f1 != **f2).into()),
+                    GreaterThan => return Ok((**f1 > **f2).into()),
+                    GreaterThanEqualsTo => return Ok((**f1 >= **f2).into()),
+                    LessThan => return Ok((**f1 < **f2).into()),
+                    LessThanEqualsTo => return Ok((**f1 <= **f2).into()),
+                    Plus => return Ok((**f1 + **f2).into()),
+                    Minus => return Ok((**f1 - **f2).into()),
+                    Multiply => return Ok((**f1 * **f2).into()),
+                    Divide => return Ok((**f1 / **f2).into()),
+                    Modulo => return Ok((**f1 % **f2).into()),
+                    _ => (),
+                },
+                #[cfg(not(feature = "no_float"))]
+                (Union::Float(f1, ..), Union::Int(n2, ..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok((**f1 == (*n2 as crate::FLOAT)).into()),
+                    NotEqualsTo => return Ok((**f1 != (*n2 as crate::FLOAT)).into()),
+                    GreaterThan => return Ok((**f1 > (*n2 as crate::FLOAT)).into()),
+                    GreaterThanEqualsTo => return Ok((**f1 >= (*n2 as crate::FLOAT)).into()),
+                    LessThan => return Ok((**f1 < (*n2 as crate::FLOAT)).into()),
+                    LessThanEqualsTo => return Ok((**f1 <= (*n2 as crate::FLOAT)).into()),
+                    Plus => return Ok((**f1 + (*n2 as crate::FLOAT)).into()),
+                    Minus => return Ok((**f1 - (*n2 as crate::FLOAT)).into()),
+                    Multiply => return Ok((**f1 * (*n2 as crate::FLOAT)).into()),
+                    Divide => return Ok((**f1 / (*n2 as crate::FLOAT)).into()),
+                    Modulo => return Ok((**f1 % (*n2 as crate::FLOAT)).into()),
+                    _ => (),
+                },
+                #[cfg(not(feature = "no_float"))]
+                (Union::Int(n1, ..), Union::Float(f2, ..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok(((*n1 as crate::FLOAT) == **f2).into()),
+                    NotEqualsTo => return Ok(((*n1 as crate::FLOAT) != **f2).into()),
+                    GreaterThan => return Ok(((*n1 as crate::FLOAT) > **f2).into()),
+                    GreaterThanEqualsTo => return Ok(((*n1 as crate::FLOAT) >= **f2).into()),
+                    LessThan => return Ok(((*n1 as crate::FLOAT) < **f2).into()),
+                    LessThanEqualsTo => return Ok(((*n1 as crate::FLOAT) <= **f2).into()),
+                    Plus => return Ok(((*n1 as crate::FLOAT) + **f2).into()),
+                    Minus => return Ok(((*n1 as crate::FLOAT) - **f2).into()),
+                    Multiply => return Ok(((*n1 as crate::FLOAT) * **f2).into()),
+                    Divide => return Ok(((*n1 as crate::FLOAT) / **f2).into()),
+                    Modulo => return Ok(((*n1 as crate::FLOAT) % **f2).into()),
+                    _ => (),
+                },
+                (Union::Str(s1, ..), Union::Str(s2, ..)) => match op_token.unwrap() {
+                    EqualsTo => return Ok((s1 == s2).into()),
+                    NotEqualsTo => return Ok((s1 != s2).into()),
+                    GreaterThan => return Ok((s1 > s2).into()),
+                    GreaterThanEqualsTo => return Ok((s1 >= s2).into()),
+                    LessThan => return Ok((s1 < s2).into()),
+                    LessThanEqualsTo => return Ok((s1 <= s2).into()),
+                    _ => (),
+                },
+                _ => (),
+            }
+
             let operands = &mut [&mut lhs, &mut rhs];
 
             if let Some((func, need_context)) =
                 get_builtin_binary_op_fn(op_token.as_ref().unwrap(), operands[0], operands[1])
             {
-                // Built-in found
+                // We may not need to bump the level because built-in's do not need it.
-                auto_restore! { let orig_level = global.level; global.level += 1 }
+                //auto_restore! { let orig_level = global.level; global.level += 1 }
 
-                let context = if need_context {
+                let context =
-                    Some((self, name.as_str(), None, &*global, pos).into())
+                    need_context.then(|| (self, name.as_str(), None, &*global, pos).into());
-                } else {
-                    None
-                };
                 return func(context, operands);
             }
 

src/func/hashing.rs

@@ -27,7 +27,8 @@ impl Hasher for StraightHasher {
     fn finish(&self) -> u64 {
         self.0
     }
-    #[inline(always)]
+    #[cold]
+    #[inline(never)]
     fn write(&mut self, _bytes: &[u8]) {
         panic!("StraightHasher can only hash u64 values");
     }
@@ -85,7 +86,7 @@ pub fn calc_var_hash<'a>(namespace: impl IntoIterator<Item = &'a str>, var_name:
         }
         count += 1;
     });
-    count.hash(s);
+    s.write_usize(count);
     var_name.hash(s);
 
     s.finish()
@@ -119,9 +120,9 @@ pub fn calc_fn_hash<'a>(
         }
         count += 1;
     });
-    count.hash(s);
+    s.write_usize(count);
     fn_name.hash(s);
-    num.hash(s);
+    s.write_usize(num);
 
     s.finish()
 }
@@ -133,13 +134,12 @@ pub fn calc_fn_hash<'a>(
 #[must_use]
 pub fn calc_fn_hash_full(base: u64, params: impl IntoIterator<Item = TypeId>) -> u64 {
     let s = &mut get_hasher();
-    base.hash(s);
     let mut count = 0;
     params.into_iter().for_each(|t| {
         t.hash(s);
         count += 1;
     });
-    count.hash(s);
+    s.write_usize(count);
 
-    s.finish()
+    s.finish() ^ base
 }

src/func/script.rs

@@ -86,7 +86,7 @@ impl Engine {
         let orig_fn_resolution_caches_len = caches.fn_resolution_caches_len();
 
         #[cfg(not(feature = "no_module"))]
-        let orig_constants = if let Some(environ) = _environ {
+        let orig_constants = _environ.map(|environ| {
             let EncapsulatedEnviron {
                 lib,
                 imports,
@@ -100,10 +100,8 @@ impl Engine {
 
             global.lib.push(lib.clone());
 
-            Some(mem::replace(&mut global.constants, constants.clone()))
+            mem::replace(&mut global.constants, constants.clone())
-        } else {
+        });
-            None
-        };
 
         #[cfg(feature = "debugging")]
         if self.is_debugger_registered() {

src/module/mod.rs

@@ -85,7 +85,7 @@ pub struct FuncInfoMetadata {
     pub return_type: Identifier,
     /// Comments.
     #[cfg(feature = "metadata")]
-    pub comments: Box<[Identifier]>,
+    pub comments: Box<[SmartString]>,
 }
 
 /// A type containing a single registered function.
@@ -292,6 +292,11 @@ impl<M: Into<Module>> AddAssign<M> for Module {
     }
 }
 
+#[inline(always)]
+fn new_hash_map<T>(size: usize) -> StraightHashMap<T> {
+    StraightHashMap::with_capacity_and_hasher(size, Default::default())
+}
+
 impl Module {
     /// Create a new [`Module`].
     ///
@@ -361,13 +366,7 @@ impl Module {
     #[inline(always)]
     pub fn set_id(&mut self, id: impl Into<ImmutableString>) -> &mut Self {
         let id = id.into();
-
+        self.id = (!id.is_empty()).then(|| id);
-        if id.is_empty() {
-            self.id = None;
-        } else {
-            self.id = Some(id);
-        }
-
         self
     }
 
@@ -691,6 +690,16 @@ impl Module {
 
         if self.is_indexed() {
             let hash_var = crate::calc_var_hash(Some(""), &ident);
+
+            // Catch hash collisions in testing environment only.
+            #[cfg(feature = "testing-environ")]
+            if let Some(_) = self.all_variables.as_ref().and_then(|f| f.get(&hash_var)) {
+                panic!(
+                    "Hash {} already exists when registering variable {}",
+                    hash_var, ident
+                );
+            }
+
             self.all_variables
                 .get_or_insert_with(Default::default)
                 .insert(hash_var, value.clone());
@@ -721,12 +730,21 @@ impl Module {
         // None + function name + number of arguments.
         let num_params = fn_def.params.len();
         let hash_script = crate::calc_fn_hash(None, &fn_def.name, num_params);
+
+        // Catch hash collisions in testing environment only.
+        #[cfg(feature = "testing-environ")]
+        if let Some(f) = self.functions.as_ref().and_then(|f| f.get(&hash_script)) {
+            panic!(
+                "Hash {} already exists when registering function {:#?}:\n{:#?}",
+                hash_script, fn_def, f
+            );
+        }
+
         #[cfg(feature = "metadata")]
         let params_info = fn_def.params.iter().map(Into::into).collect();
+
         self.functions
-            .get_or_insert_with(|| {
+            .get_or_insert_with(|| new_hash_map(FN_MAP_SIZE))
-                StraightHashMap::with_capacity_and_hasher(FN_MAP_SIZE, Default::default())
-            })
             .insert(
                 hash_script,
                 FuncInfo {
@@ -1052,6 +1070,15 @@ impl Module {
         let hash_script = calc_fn_hash(None, name, param_types.len());
         let hash_fn = calc_fn_hash_full(hash_script, param_types.iter().copied());
 
+        // Catch hash collisions in testing environment only.
+        #[cfg(feature = "testing-environ")]
+        if let Some(f) = self.functions.as_ref().and_then(|f| f.get(&hash_script)) {
+            panic!(
+                "Hash {} already exists when registering function {}:\n{:#?}",
+                hash_script, name, f
+            );
+        }
+
         if is_dynamic {
             self.dynamic_functions_filter
                 .get_or_insert_with(Default::default)
@@ -1059,9 +1086,7 @@ impl Module {
         }
 
         self.functions
-            .get_or_insert_with(|| {
+            .get_or_insert_with(|| new_hash_map(FN_MAP_SIZE))
-                StraightHashMap::with_capacity_and_hasher(FN_MAP_SIZE, Default::default())
-            })
             .insert(
                 hash_fn,
                 FuncInfo {
@@ -1781,9 +1806,9 @@ impl Module {
             let others_len = functions.len();
 
             for (&k, f) in functions.iter() {
-                let map = self.functions.get_or_insert_with(|| {
+                let map = self
-                    StraightHashMap::with_capacity_and_hasher(others_len, Default::default())
+                    .functions
-                });
+                    .get_or_insert_with(|| new_hash_map(FN_MAP_SIZE));
                 map.reserve(others_len);
                 map.entry(k).or_insert_with(|| f.clone());
             }
@@ -2083,9 +2108,10 @@ impl Module {
         ast: &crate::AST,
         engine: &crate::Engine,
     ) -> RhaiResultOf<Self> {
+        let mut scope = scope;
         let global = &mut crate::eval::GlobalRuntimeState::new(engine);
 
-        Self::eval_ast_as_new_raw(engine, scope, global, ast)
+        Self::eval_ast_as_new_raw(engine, &mut scope, global, ast)
     }
     /// Create a new [`Module`] by evaluating an [`AST`][crate::AST].
     ///
@@ -2101,13 +2127,12 @@ impl Module {
     #[cfg(not(feature = "no_module"))]
     pub fn eval_ast_as_new_raw(
         engine: &crate::Engine,
-        scope: crate::Scope,
+        scope: &mut crate::Scope,
         global: &mut crate::eval::GlobalRuntimeState,
         ast: &crate::AST,
     ) -> RhaiResultOf<Self> {
-        let mut scope = scope;
-
         // Save global state
+        let orig_scope_len = scope.len();
         let orig_imports_len = global.num_imports();
         let orig_source = global.source.clone();
 
@@ -2120,7 +2145,7 @@ impl Module {
         // Run the script
         let caches = &mut crate::eval::Caches::new();
 
-        let result = engine.eval_ast_with_scope_raw(global, caches, &mut scope, ast);
+        let result = engine.eval_ast_with_scope_raw(global, caches, scope, ast);
 
         // Create new module
         let mut module = Module::new();
@@ -2162,7 +2187,9 @@ impl Module {
         });
 
         // Variables with an alias left in the scope become module variables
-        for (_name, mut value, mut aliases) in scope {
+        while scope.len() > orig_scope_len {
+            let (_name, mut value, mut aliases) = scope.pop_entry().expect("not empty");
+
             value.deep_scan(|v| {
                 if let Some(fn_ptr) = v.downcast_mut::<crate::FnPtr>() {
                     fn_ptr.set_encapsulated_environ(Some(environ.clone()));
@@ -2257,6 +2284,16 @@ impl Module {
             if let Some(ref v) = module.variables {
                 for (var_name, value) in v.iter() {
                     let hash_var = crate::calc_var_hash(path.iter().copied(), var_name);
+
+                    // Catch hash collisions in testing environment only.
+                    #[cfg(feature = "testing-environ")]
+                    if let Some(_) = variables.get(&hash_var) {
+                        panic!(
+                            "Hash {} already exists when indexing variable {}",
+                            hash_var, var_name
+                        );
+                    }
+
                     variables.insert(hash_var, value.clone());
                 }
             }
@@ -2272,6 +2309,15 @@ impl Module {
             for (&hash, f) in module.functions.iter().flatten() {
                 match f.metadata.namespace {
                     FnNamespace::Global => {
+                        // Catch hash collisions in testing environment only.
+                        #[cfg(feature = "testing-environ")]
+                        if let Some(fx) = functions.get(&hash) {
+                            panic!(
+                                "Hash {} already exists when indexing function {:#?}:\n{:#?}",
+                                hash, f.func, fx
+                            );
+                        }
+
                         // Flatten all functions with global namespace
                         functions.insert(hash, f.func.clone());
                         contains_indexed_global_functions = true;
@@ -2289,6 +2335,16 @@ impl Module {
                         f.metadata.name.as_str(),
                         &f.metadata.param_types,
                     );
+
+                    // Catch hash collisions in testing environment only.
+                    #[cfg(feature = "testing-environ")]
+                    if let Some(fx) = functions.get(&hash_qualified_fn) {
+                        panic!(
+                            "Hash {} already exists when indexing function {:#?}:\n{:#?}",
+                            hash_qualified_fn, f.func, fx
+                        );
+                    }
+
                     functions.insert(hash_qualified_fn, f.func.clone());
                 } else if cfg!(not(feature = "no_function")) {
                     let hash_qualified_script = crate::calc_fn_hash(
@@ -2296,6 +2352,16 @@ impl Module {
                         &f.metadata.name,
                         f.metadata.num_params,
                     );
+
+                    // Catch hash collisions in testing environment only.
+                    #[cfg(feature = "testing-environ")]
+                    if let Some(fx) = functions.get(&hash_qualified_script) {
+                        panic!(
+                            "Hash {} already exists when indexing function {:#?}:\n{:#?}",
+                            hash_qualified_script, f.func, fx
+                        );
+                    }
+
                     functions.insert(hash_qualified_script, f.func.clone());
                 }
             }
@@ -2305,14 +2371,9 @@ impl Module {
 
         if !self.is_indexed() {
             let mut path = Vec::with_capacity(4);
-            let mut variables = StraightHashMap::with_capacity_and_hasher(
+            let mut variables = new_hash_map(self.variables.as_deref().map_or(0, BTreeMap::len));
-                self.variables.as_deref().map_or(0, BTreeMap::len),
+            let mut functions =
-                Default::default(),
+                new_hash_map(self.functions.as_ref().map_or(0, StraightHashMap::len));
-            );
-            let mut functions = StraightHashMap::with_capacity_and_hasher(
-                self.functions.as_ref().map_or(0, StraightHashMap::len),
-                Default::default(),
-            );
             let mut type_iterators = BTreeMap::new();
 
             path.push("");
@@ -2328,21 +2389,9 @@ impl Module {
             self.flags
                 .set(ModuleFlags::INDEXED_GLOBAL_FUNCTIONS, has_global_functions);
 
-            self.all_variables = if variables.is_empty() {
+            self.all_variables = (!variables.is_empty()).then(|| variables.into());
-                None
+            self.all_functions = (!functions.is_empty()).then(|| functions.into());
-            } else {
+            self.all_type_iterators = (!type_iterators.is_empty()).then(|| type_iterators.into());
-                Some(variables.into())
-            };
-            self.all_functions = if functions.is_empty() {
-                None
-            } else {
-                Some(functions.into())
-            };
-            self.all_type_iterators = if type_iterators.is_empty() {
-                None
-            } else {
-                Some(type_iterators.into())
-            };
 
             self.flags |= ModuleFlags::INDEXED;
         }

src/module/resolvers/file.rs

@@ -239,14 +239,7 @@ impl FileModuleResolver {
         if !self.cache_enabled {
             return false;
         }
-
+        locked_read(&self.cache).contains_key(path.as_ref())
-        let cache = locked_read(&self.cache);
-
-        if cache.is_empty() {
-            false
-        } else {
-            cache.contains_key(path.as_ref())
-        }
     }
     /// Empty the internal cache.
     #[inline]
@@ -290,15 +283,15 @@ impl FileModuleResolver {
     fn impl_resolve(
         &self,
         engine: &Engine,
-        global: Option<&mut GlobalRuntimeState>,
+        global: &mut GlobalRuntimeState,
+        scope: &mut Scope,
         source: Option<&str>,
         path: &str,
         pos: Position,
     ) -> Result<SharedModule, Box<crate::EvalAltResult>> {
         // Load relative paths from source if there is no base path specified
         let source_path = global
-            .as_ref()
+            .source()
-            .and_then(|g| g.source())
             .or(source)
             .and_then(|p| Path::new(p).parent());
 
@@ -321,14 +314,9 @@ impl FileModuleResolver {
 
         ast.set_source(path);
 
-        let scope = Scope::new();
+        let m: Shared<_> = Module::eval_ast_as_new_raw(engine, scope, global, &ast)
-
+            .map_err(|err| Box::new(ERR::ErrorInModule(path.to_string(), err, pos)))?
-        let m: Shared<_> = match global {
+            .into();
-            Some(global) => Module::eval_ast_as_new_raw(engine, scope, global, &ast),
-            None => Module::eval_ast_as_new(scope, &ast, engine),
-        }
-        .map_err(|err| Box::new(ERR::ErrorInModule(path.to_string(), err, pos)))?
-        .into();
 
         if self.is_cache_enabled() {
             locked_write(&self.cache).insert(file_path, m.clone());
@@ -343,10 +331,11 @@ impl ModuleResolver for FileModuleResolver {
         &self,
         engine: &Engine,
         global: &mut GlobalRuntimeState,
+        scope: &mut Scope,
         path: &str,
         pos: Position,
     ) -> RhaiResultOf<SharedModule> {
-        self.impl_resolve(engine, Some(global), None, path, pos)
+        self.impl_resolve(engine, global, scope, None, path, pos)
     }
 
     #[inline(always)]
@@ -357,7 +346,9 @@ impl ModuleResolver for FileModuleResolver {
         path: &str,
         pos: Position,
     ) -> RhaiResultOf<SharedModule> {
-        self.impl_resolve(engine, None, source, path, pos)
+        let global = &mut GlobalRuntimeState::new(engine);
+        let scope = &mut Scope::new();
+        self.impl_resolve(engine, global, scope, source, path, pos)
     }
 
     /// Resolve an `AST` based on a path string.

src/module/resolvers/mod.rs

@@ -1,6 +1,6 @@
 use crate::eval::GlobalRuntimeState;
 use crate::func::SendSync;
-use crate::{Engine, Position, RhaiResultOf, SharedModule, AST};
+use crate::{Engine, Position, RhaiResultOf, Scope, SharedModule, AST};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -27,15 +27,17 @@ pub trait ModuleResolver: SendSync {
         pos: Position,
     ) -> RhaiResultOf<SharedModule>;
 
-    /// Resolve a module based on a path string, given a [`GlobalRuntimeState`].
+    /// Resolve a module based on a path string, given a [`GlobalRuntimeState`] and the current [`Scope`].
     ///
     /// # WARNING - Low Level API
     ///
     /// This function is very low level.
+    #[allow(unused_variables)]
     fn resolve_raw(
         &self,
         engine: &Engine,
         global: &mut GlobalRuntimeState,
+        scope: &mut Scope,
         path: &str,
         pos: Position,
     ) -> RhaiResultOf<SharedModule> {

src/module/resolvers/stat.rs

@@ -73,11 +73,7 @@ impl StaticModuleResolver {
     #[inline(always)]
     #[must_use]
     pub fn contains_path(&self, path: &str) -> bool {
-        if self.0.is_empty() {
+        self.0.contains_key(path)
-            false
-        } else {
-            self.0.contains_key(path)
-        }
     }
     /// Get an iterator of all the [modules][Module].
     #[inline]
@@ -123,9 +119,7 @@ impl StaticModuleResolver {
     /// Existing modules of the same path name are overwritten.
     #[inline]
     pub fn merge(&mut self, other: Self) -> &mut Self {
-        if !other.is_empty() {
+        self.0.extend(other.0.into_iter());
-            self.0.extend(other.0.into_iter());
-        }
         self
     }
 }

src/optimizer.rs

@@ -5,7 +5,9 @@ use crate::ast::{
     ASTFlags, Expr, FlowControl, OpAssignment, Stmt, StmtBlock, StmtBlockContainer,
     SwitchCasesCollection,
 };
-use crate::engine::{KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_FN_PTR, KEYWORD_PRINT, KEYWORD_TYPE_OF};
+use crate::engine::{
+    KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_FN_PTR, KEYWORD_PRINT, KEYWORD_TYPE_OF, OP_NOT,
+};
 use crate::eval::{Caches, GlobalRuntimeState};
 use crate::func::builtin::get_builtin_binary_op_fn;
 use crate::func::hashing::get_hasher;
@@ -25,9 +27,6 @@ use std::{
     mem,
 };
 
-/// Standard not operator.
-const OP_NOT: &str = Token::Bang.literal_syntax();
-
 /// Level of optimization performed.
 #[derive(Debug, Eq, PartialEq, Hash, Clone, Copy)]
 #[non_exhaustive]
@@ -564,16 +563,14 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
             }
 
             // Then check ranges
-            if value.is_int() && !ranges.is_empty() {
+            if !ranges.is_empty() {
-                let value = value.as_int().unwrap();
-
                 // Only one range or all ranges without conditions
                 if ranges.len() == 1
                     || ranges
                         .iter()
                         .all(|r| expressions[r.index()].is_always_true())
                 {
-                    if let Some(r) = ranges.iter().find(|r| r.contains(value)) {
+                    if let Some(r) = ranges.iter().find(|r| r.contains(&value)) {
                         let range_block = &mut expressions[r.index()];
 
                         if range_block.is_always_true() {
@@ -620,7 +617,7 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
 
                     let old_ranges_len = ranges.len();
 
-                    ranges.retain(|r| r.contains(value));
+                    ranges.retain(|r| r.contains(&value));
 
                     if ranges.len() != old_ranges_len {
                         state.set_dirty();
@@ -1140,13 +1137,9 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
                 _ if x.args.len() == 2 && x.op_token.is_some() && (state.engine.fast_operators() || !state.engine.has_native_fn_override(x.hashes.native(), &arg_types)) => {
                     if let Some(result) = get_builtin_binary_op_fn(x.op_token.as_ref().unwrap(), &arg_values[0], &arg_values[1])
                         .and_then(|(f, ctx)| {
-                            let context = if ctx {
+                            let context = ctx.then(|| (state.engine, x.name.as_str(), None, &state.global, *pos).into());
-                                Some((state.engine, x.name.as_str(), None, &state.global, *pos).into())
-                            } else {
-                                None
-                            };
                             let (first, second) = arg_values.split_first_mut().unwrap();
-                            (f)(context, &mut [ first, &mut second[0] ]).ok()
+                            f(context, &mut [ first, &mut second[0] ]).ok()
                         }) {
                             state.set_dirty();
                             *expr = Expr::from_dynamic(result, *pos);

src/packages/array_basic.rs

@@ -5,6 +5,7 @@ use crate::engine::OP_EQUALS;
 use crate::eval::{calc_index, calc_offset_len};
 use crate::module::ModuleFlags;
 use crate::plugin::*;
+
 use crate::{
     def_package, Array, Dynamic, ExclusiveRange, FnPtr, InclusiveRange, NativeCallContext,
     Position, RhaiResultOf, StaticVec, ERR, INT, MAX_USIZE_INT,
@@ -237,7 +238,7 @@ pub mod array_functions {
         #[cfg(not(feature = "unchecked"))]
         if _ctx.engine().max_array_size() > 0 {
             let pad = len - array.len();
-            let (a, m, s) = Dynamic::calc_array_sizes(array);
+            let (a, m, s) = crate::eval::calc_array_sizes(array);
             let (ax, mx, sx) = item.calc_data_sizes(true);
 
             _ctx.engine()

src/packages/lang_core.rs

@@ -7,6 +7,7 @@ use crate::{Dynamic, RhaiResultOf, ERR, INT};
 use std::prelude::v1::*;
 
 #[cfg(not(feature = "no_float"))]
+#[cfg(not(feature = "no_std"))]
 use crate::FLOAT;
 
 def_package! {
@@ -287,7 +288,8 @@ fn collect_fn_metadata(
 
     #[cfg(not(feature = "no_module"))]
     {
-        use crate::{tokenizer::Token::DoubleColon, Shared, SmartString};
+        use crate::engine::NAMESPACE_SEPARATOR;
+        use crate::{Shared, SmartString};
 
         // Recursively scan modules for script-defined functions.
         fn scan_module(
@@ -305,7 +307,7 @@ fn collect_fn_metadata(
                 use std::fmt::Write;
 
                 let mut ns = SmartString::new_const();
-                write!(&mut ns, "{namespace}{}{name}", DoubleColon.literal_syntax()).unwrap();
+                write!(&mut ns, "{namespace}{}{name}", NAMESPACE_SEPARATOR).unwrap();
                 scan_module(engine, list, &ns, m, filter);
             }
         }

src/parser.rs

@@ -7,25 +7,24 @@ use crate::ast::{
     FnCallHashes, Ident, Namespace, OpAssignment, RangeCase, ScriptFnDef, Stmt, StmtBlock,
     StmtBlockContainer, SwitchCasesCollection,
 };
-use crate::engine::{Precedence, KEYWORD_THIS, OP_CONTAINS};
+use crate::engine::{Precedence, KEYWORD_THIS, OP_CONTAINS, OP_NOT};
 use crate::eval::{Caches, GlobalRuntimeState};
 use crate::func::{hashing::get_hasher, StraightHashMap};
 use crate::tokenizer::{
-    is_keyword_function, is_valid_function_name, is_valid_identifier, Token, TokenStream,
+    is_reserved_keyword_or_symbol, is_valid_function_name, is_valid_identifier, Token, TokenStream,
     TokenizerControl,
 };
-use crate::types::dynamic::AccessMode;
+use crate::types::dynamic::{AccessMode, Union};
 use crate::types::StringsInterner;
 use crate::{
     calc_fn_hash, Dynamic, Engine, EvalAltResult, EvalContext, ExclusiveRange, FnArgsVec,
     Identifier, ImmutableString, InclusiveRange, LexError, OptimizationLevel, ParseError, Position,
-    Scope, Shared, SmartString, StaticVec, AST, INT, PERR,
+    Scope, Shared, SmartString, StaticVec, AST, PERR,
 };
 use bitflags::bitflags;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
-    collections::BTreeMap,
     convert::TryFrom,
     fmt,
     hash::{Hash, Hasher},
@@ -42,9 +41,6 @@ const SCOPE_SEARCH_BARRIER_MARKER: &str = "$ BARRIER $";
 /// The message: `TokenStream` never ends
 const NEVER_ENDS: &str = "`Token`";
 
-/// Unroll `switch` ranges no larger than this.
-const SMALL_SWITCH_RANGE: INT = 16;
-
 /// _(internals)_ A type that encapsulates the current state of the parser.
 /// Exported under the `internals` feature only.
 pub struct ParseState<'e, 's> {
@@ -218,11 +214,7 @@ impl<'e, 's> ParseState<'e, 's> {
             self.allow_capture = true;
         }
 
-        let index = if hit_barrier {
+        let index = (!hit_barrier).then(|| NonZeroUsize::new(index)).flatten();
-            None
-        } else {
-            NonZeroUsize::new(index)
-        };
 
         (index, is_func_name)
     }
@@ -986,7 +978,7 @@ impl Engine {
         settings.pos = eat_token(input, Token::MapStart);
 
         let mut map = StaticVec::<(Ident, Expr)>::new();
-        let mut template = BTreeMap::<Identifier, crate::Dynamic>::new();
+        let mut template = std::collections::BTreeMap::<Identifier, crate::Dynamic>::new();
 
         loop {
             const MISSING_RBRACE: &str = "to end this object map literal";
@@ -1121,7 +1113,7 @@ impl Engine {
         }
 
         let mut expressions = StaticVec::<ConditionalExpr>::new();
-        let mut cases = BTreeMap::<u64, CaseBlocksList>::new();
+        let mut cases = StraightHashMap::<CaseBlocksList>::default();
         let mut ranges = StaticVec::<RangeCase>::new();
         let mut def_case = None;
         let mut def_case_pos = Position::NONE;
@@ -1216,7 +1208,6 @@ impl Engine {
                     let stmt_block: StmtBlock = stmt.into();
                     (Expr::Stmt(stmt_block.into()), need_comma)
                 };
-            let has_condition = !matches!(condition, Expr::BoolConstant(true, ..));
 
             expressions.push((condition, action_expr).into());
             let index = expressions.len() - 1;
@@ -1240,29 +1231,28 @@ impl Engine {
 
                     if let Some(mut r) = range_value {
                         if !r.is_empty() {
-                            // Do not unroll ranges if there are previous non-unrolled ranges
+                            // Other range
-                            if !has_condition && ranges.is_empty() && r.len() <= SMALL_SWITCH_RANGE
+                            r.set_index(index);
-                            {
+                            ranges.push(r);
-                                // Unroll small range
-                                r.into_iter().for_each(|n| {
-                                    let hasher = &mut get_hasher();
-                                    Dynamic::from_int(n).hash(hasher);
-                                    cases
-                                        .entry(hasher.finish())
-                                        .and_modify(|cases| cases.push(index))
-                                        .or_insert_with(|| [index].into());
-                                });
-                            } else {
-                                // Other range
-                                r.set_index(index);
-                                ranges.push(r);
-                            }
                         }
                         continue;
                     }
 
-                    if value.is_int() && !ranges.is_empty() {
+                    if !ranges.is_empty() {
-                        return Err(PERR::WrongSwitchIntegerCase.into_err(expr.start_position()));
+                        let forbidden = match value {
+                            Dynamic(Union::Int(..)) => true,
+                            #[cfg(not(feature = "no_float"))]
+                            Dynamic(Union::Float(..)) => true,
+                            #[cfg(feature = "decimal")]
+                            Dynamic(Union::Decimal(..)) => true,
+                            _ => false,
+                        };
+
+                        if forbidden {
+                            return Err(
+                                PERR::WrongSwitchIntegerCase.into_err(expr.start_position())
+                            );
+                        }
                     }
 
                     let hasher = &mut get_hasher();
@@ -1299,6 +1289,10 @@ impl Engine {
             }
         }
 
+        expressions.shrink_to_fit();
+        cases.shrink_to_fit();
+        ranges.shrink_to_fit();
+
         let cases = SwitchCasesCollection {
             expressions,
             cases,
@@ -1398,20 +1392,26 @@ impl Engine {
                     .into(),
             )),
             // Loops are allowed to act as expressions
-            Token::While | Token::Loop if settings.has_option(LangOptions::LOOP_EXPR) => {
+            Token::While | Token::Loop
+                if self.allow_looping() && settings.has_option(LangOptions::LOOP_EXPR) =>
+            {
                 Expr::Stmt(Box::new(
                     self.parse_while_loop(input, state, lib, settings.level_up()?)?
                         .into(),
                 ))
             }
-            Token::Do if settings.has_option(LangOptions::LOOP_EXPR) => Expr::Stmt(Box::new(
+            Token::Do if self.allow_looping() && settings.has_option(LangOptions::LOOP_EXPR) => {
-                self.parse_do(input, state, lib, settings.level_up()?)?
+                Expr::Stmt(Box::new(
-                    .into(),
+                    self.parse_do(input, state, lib, settings.level_up()?)?
-            )),
+                        .into(),
-            Token::For if settings.has_option(LangOptions::LOOP_EXPR) => Expr::Stmt(Box::new(
+                ))
-                self.parse_for(input, state, lib, settings.level_up()?)?
+            }
-                    .into(),
+            Token::For if self.allow_looping() && settings.has_option(LangOptions::LOOP_EXPR) => {
-            )),
+                Expr::Stmt(Box::new(
+                    self.parse_for(input, state, lib, settings.level_up()?)?
+                        .into(),
+                ))
+            }
             // Switch statement is allowed to act as expressions
             Token::Switch if settings.has_option(LangOptions::SWITCH_EXPR) => Expr::Stmt(Box::new(
                 self.parse_switch(input, state, lib, settings.level_up()?)?
@@ -1665,7 +1665,9 @@ impl Engine {
 
                 match input.peek().expect(NEVER_ENDS).0 {
                     // Function call is allowed to have reserved keyword
-                    Token::LeftParen | Token::Bang | Token::Unit if is_keyword_function(&s).0 => {
+                    Token::LeftParen | Token::Bang | Token::Unit
+                        if is_reserved_keyword_or_symbol(&s).1 =>
+                    {
                         Expr::Variable(
                             (None, ns, 0, state.get_interned_string(*s)).into(),
                             None,
@@ -1722,7 +1724,7 @@ impl Engine {
         lib: &mut FnLib,
         settings: ParseSettings,
         mut lhs: Expr,
-        options: ChainingFlags,
+        _options: ChainingFlags,
     ) -> ParseResult<Expr> {
         let mut settings = settings;
 
@@ -1783,7 +1785,7 @@ impl Engine {
                 // Disallowed module separator
                 #[cfg(not(feature = "no_module"))]
                 (_, token @ Token::DoubleColon)
-                    if options.contains(ChainingFlags::DISALLOW_NAMESPACES) =>
+                    if _options.contains(ChainingFlags::DISALLOW_NAMESPACES) =>
                 {
                     return Err(LexError::ImproperSymbol(
                         token.literal_syntax().into(),
@@ -1824,7 +1826,7 @@ impl Engine {
                             // Prevents capturing of the object properties as vars: xxx.<var>
                             state.allow_capture = false;
                         }
-                        (Token::Reserved(s), ..) if is_keyword_function(s).1 => (),
+                        (Token::Reserved(s), ..) if is_reserved_keyword_or_symbol(s).2 => (),
                         (Token::Reserved(s), pos) => {
                             return Err(PERR::Reserved(s.to_string()).into_err(*pos))
                         }
@@ -2352,12 +2354,7 @@ impl Engine {
 
             let op = op_token.to_string();
             let hash = calc_fn_hash(None, &op, 2);
-            let is_valid_script_function = is_valid_function_name(&op);
+            let native_only = !is_valid_function_name(&op);
-            let operator_token = if is_valid_script_function {
-                None
-            } else {
-                Some(op_token.clone())
-            };
 
             let mut args = FnArgsVec::new_const();
             args.push(root);
@@ -2369,7 +2366,7 @@ impl Engine {
                 name: state.get_interned_string(&op),
                 hashes: FnCallHashes::from_native_only(hash),
                 args,
-                op_token: operator_token,
+                op_token: native_only.then(|| op_token.clone()),
                 capture_parent_scope: false,
             };
 
@@ -2418,14 +2415,13 @@ impl Engine {
                         fn_call
                     } else {
                         // Put a `!` call in front
-                        let op = Token::Bang.literal_syntax();
                         let mut args = FnArgsVec::new_const();
                         args.push(fn_call);
 
                         let not_base = FnCallExpr {
                             namespace: Namespace::NONE,
-                            name: state.get_interned_string(op),
+                            name: state.get_interned_string(OP_NOT),
-                            hashes: FnCallHashes::from_native_only(calc_fn_hash(None, op, 1)),
+                            hashes: FnCallHashes::from_native_only(calc_fn_hash(None, OP_NOT, 1)),
                             args,
                             op_token: Some(Token::Bang),
                             capture_parent_scope: false,
@@ -2442,10 +2438,10 @@ impl Engine {
                         .and_then(|m| m.get(s.as_str()))
                         .map_or(false, Option::is_some) =>
                 {
-                    op_base.hashes = if is_valid_script_function {
+                    op_base.hashes = if native_only {
-                        FnCallHashes::from_hash(calc_fn_hash(None, &s, 2))
-                    } else {
                         FnCallHashes::from_native_only(calc_fn_hash(None, &s, 2))
+                    } else {
+                        FnCallHashes::from_hash(calc_fn_hash(None, &s, 2))
                     };
                     op_base.into_fn_call_expr(pos)
                 }
@@ -3081,8 +3077,7 @@ impl Engine {
         let (id, id_pos) = parse_var_name(input)?;
 
         let (alias, alias_pos) = if match_token(input, Token::As).0 {
-            let (name, pos) = parse_var_name(input)?;
+            parse_var_name(input).map(|(name, pos)| (Some(name), pos))?
-            (Some(name), pos)
         } else {
             (None, Position::NONE)
         };
@@ -3788,7 +3783,7 @@ impl Engine {
                     (.., pos) => {
                         return Err(PERR::MissingToken(
                             Token::Pipe.into(),
-                            "to close the parameters list of anonymous function".into(),
+                            "to close the parameters list of anonymous function or closure".into(),
                         )
                         .into_err(pos))
                     }

src/tests.rs

@@ -13,6 +13,7 @@ fn check_struct_sizes() {
         feature = "only_i32",
         any(feature = "no_float", feature = "f32_float")
     ));
+    const WORD_SIZE: usize = size_of::<usize>();
 
     assert_eq!(size_of::<Dynamic>(), if PACKED { 8 } else { 16 });
     assert_eq!(size_of::<Option<Dynamic>>(), if PACKED { 8 } else { 16 });
@@ -20,10 +21,7 @@ fn check_struct_sizes() {
         size_of::<Position>(),
         if cfg!(feature = "no_position") { 0 } else { 4 }
     );
-    assert_eq!(
+    assert_eq!(size_of::<tokenizer::Token>(), 2 * WORD_SIZE);
-        size_of::<tokenizer::Token>(),
-        if IS_32_BIT { 8 } else { 16 }
-    );
     assert_eq!(size_of::<ast::Expr>(), if PACKED { 12 } else { 16 });
     assert_eq!(size_of::<Option<ast::Expr>>(), if PACKED { 12 } else { 16 });
     assert_eq!(size_of::<ast::Stmt>(), if IS_32_BIT { 12 } else { 16 });
@@ -34,40 +32,41 @@ fn check_struct_sizes() {
 
     #[cfg(feature = "internals")]
     {
-        assert_eq!(
+        assert_eq!(size_of::<CallableFunction>(), 3 * WORD_SIZE);
-            size_of::<CallableFunction>(),
+        assert_eq!(size_of::<module::FuncInfo>(), 4 * WORD_SIZE);
-            if IS_32_BIT { 12 } else { 24 }
-        );
-        assert_eq!(
-            size_of::<module::FuncInfo>(),
-            if IS_32_BIT { 16 } else { 32 }
-        );
     }
 
-    #[cfg(target_pointer_width = "64")]
+    // The following only on 64-bit platforms
-    {
+
-        assert_eq!(size_of::<Scope>(), 536);
+    if !cfg!(target_pointer_width = "64") {
-        assert_eq!(
+        return;
-            size_of::<FnPtr>(),
-            if cfg!(feature = "no_function") {
-                72
-            } else {
-                80
-            }
-        );
-        assert_eq!(size_of::<LexError>(), 56);
-        assert_eq!(
-            size_of::<ParseError>(),
-            if cfg!(feature = "no_position") { 8 } else { 16 }
-        );
-        assert_eq!(size_of::<EvalAltResult>(), 64);
-        assert_eq!(
-            size_of::<NativeCallContext>(),
-            if cfg!(feature = "no_position") {
-                48
-            } else {
-                56
-            }
-        );
     }
+
+    assert_eq!(size_of::<Scope>(), 536);
+    assert_eq!(
+        size_of::<FnPtr>(),
+        80 - if cfg!(feature = "no_function") {
+            WORD_SIZE
+        } else {
+            0
+        }
+    );
+    assert_eq!(size_of::<LexError>(), 56);
+    assert_eq!(
+        size_of::<ParseError>(),
+        16 - if cfg!(feature = "no_position") {
+            WORD_SIZE
+        } else {
+            0
+        }
+    );
+    assert_eq!(size_of::<EvalAltResult>(), 64);
+    assert_eq!(
+        size_of::<NativeCallContext>(),
+        56 - if cfg!(feature = "no_position") {
+            WORD_SIZE
+        } else {
+            0
+        }
+    );
 }

src/tokenizer.rs

@@ -1,9 +1,6 @@
 //! Main module defining the lexer and parser.
 
-use crate::engine::{
+use crate::engine::Precedence;
-    Precedence, KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_FN_PTR, KEYWORD_FN_PTR_CALL,
-    KEYWORD_FN_PTR_CURRY, KEYWORD_IS_DEF_VAR, KEYWORD_PRINT, KEYWORD_THIS, KEYWORD_TYPE_OF,
-};
 use crate::func::native::OnParseTokenCallback;
 use crate::{Engine, Identifier, LexError, Position, SmartString, StaticVec, INT, UNSIGNED_INT};
 use smallvec::SmallVec;
@@ -308,6 +305,348 @@ impl fmt::Display for Token {
     }
 }
 
+// Table-driven keyword recognizer generated by GNU gperf on the file `tools/keywords.txt`.
+//
+// When adding new keywords, make sure to update `tools/keywords.txt` and re-generate this.
+
+const MIN_KEYWORD_LEN: usize = 1;
+const MAX_KEYWORD_LEN: usize = 8;
+const MIN_KEYWORD_HASH_VALUE: usize = 1;
+const MAX_KEYWORD_HASH_VALUE: usize = 152;
+
+static KEYWORD_ASSOC_VALUES: [u8; 257] = [
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 115, 153, 100, 153, 110,
+    105, 40, 80, 2, 20, 25, 125, 95, 15, 40, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 55,
+    35, 10, 5, 0, 30, 110, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 120, 105, 100, 85, 90, 153, 125, 5,
+    0, 125, 35, 10, 100, 153, 20, 0, 153, 10, 0, 45, 55, 0, 153, 50, 55, 5, 0, 153, 0, 0, 35, 153,
+    45, 50, 30, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153, 153,
+    153,
+];
+static KEYWORDS_LIST: [(&str, Token); 153] = [
+    ("", Token::EOF),
+    (">", Token::GreaterThan),
+    (">=", Token::GreaterThanEqualsTo),
+    (")", Token::RightParen),
+    ("", Token::EOF),
+    ("const", Token::Const),
+    ("=", Token::Equals),
+    ("==", Token::EqualsTo),
+    ("continue", Token::Continue),
+    ("", Token::EOF),
+    ("catch", Token::Catch),
+    ("<", Token::LessThan),
+    ("<=", Token::LessThanEqualsTo),
+    ("for", Token::For),
+    ("loop", Token::Loop),
+    ("", Token::EOF),
+    (".", Token::Period),
+    ("<<", Token::LeftShift),
+    ("<<=", Token::LeftShiftAssign),
+    ("", Token::EOF),
+    ("false", Token::False),
+    ("*", Token::Multiply),
+    ("*=", Token::MultiplyAssign),
+    ("let", Token::Let),
+    ("", Token::EOF),
+    ("while", Token::While),
+    ("+", Token::Plus),
+    ("+=", Token::PlusAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("throw", Token::Throw),
+    ("}", Token::RightBrace),
+    (">>", Token::RightShift),
+    (">>=", Token::RightShiftAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    (";", Token::SemiColon),
+    ("=>", Token::DoubleArrow),
+    ("", Token::EOF),
+    ("else", Token::Else),
+    ("", Token::EOF),
+    ("/", Token::Divide),
+    ("/=", Token::DivideAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("{", Token::LeftBrace),
+    ("**", Token::PowerOf),
+    ("**=", Token::PowerOfAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("|", Token::Pipe),
+    ("|=", Token::OrAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    (":", Token::Colon),
+    ("..", Token::ExclusiveRange),
+    ("..=", Token::InclusiveRange),
+    ("", Token::EOF),
+    ("until", Token::Until),
+    ("switch", Token::Switch),
+    #[cfg(not(feature = "no_function"))]
+    ("private", Token::Private),
+    #[cfg(feature = "no_function")]
+    ("", Token::EOF),
+    ("try", Token::Try),
+    ("true", Token::True),
+    ("break", Token::Break),
+    ("return", Token::Return),
+    #[cfg(not(feature = "no_function"))]
+    ("fn", Token::Fn),
+    #[cfg(feature = "no_function")]
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    #[cfg(not(feature = "no_module"))]
+    ("import", Token::Import),
+    #[cfg(feature = "no_module")]
+    ("", Token::EOF),
+    #[cfg(not(feature = "no_object"))]
+    ("?.", Token::Elvis),
+    #[cfg(feature = "no_object")]
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    #[cfg(not(feature = "no_module"))]
+    ("export", Token::Export),
+    #[cfg(feature = "no_module")]
+    ("", Token::EOF),
+    ("in", Token::In),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("(", Token::LeftParen),
+    ("||", Token::Or),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("^", Token::XOr),
+    ("^=", Token::XOrAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("_", Token::Underscore),
+    ("::", Token::DoubleColon),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("-", Token::Minus),
+    ("-=", Token::MinusAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("]", Token::RightBracket),
+    ("()", Token::Unit),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("&", Token::Ampersand),
+    ("&=", Token::AndAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("%", Token::Modulo),
+    ("%=", Token::ModuloAssign),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("!", Token::Bang),
+    ("!=", Token::NotEqualsTo),
+    ("!in", Token::NotIn),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("[", Token::LeftBracket),
+    ("if", Token::If),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    (",Token::", Token::Comma),
+    ("do", Token::Do),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    #[cfg(not(feature = "no_module"))]
+    ("as", Token::As),
+    #[cfg(feature = "no_module")]
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    #[cfg(not(feature = "no_index"))]
+    ("?[", Token::QuestionBracket),
+    #[cfg(feature = "no_index")]
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("??", Token::DoubleQuestion),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("&&", Token::And),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("", Token::EOF),
+    ("#{", Token::MapStart),
+];
+
+// Table-driven reserved symbol recognizer generated by GNU gperf on the file `tools/reserved.txt`.
+//
+// When adding new reserved symbols, make sure to update `tools/reserved.txt` and re-generate this.
+
+const MIN_RESERVED_LEN: usize = 1;
+const MAX_RESERVED_LEN: usize = 10;
+const MIN_RESERVED_HASH_VALUE: usize = 1;
+const MAX_RESERVED_HASH_VALUE: usize = 112;
+
+static RESERVED_ASSOC_VALUES: [u8; 256] = [
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 35, 113, 45, 25, 113,
+    113, 113, 60, 55, 50, 50, 113, 15, 0, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    10, 85, 45, 5, 55, 50, 5, 113, 113, 113, 113, 113, 85, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 35, 113, 113, 113, 55, 113, 10, 40,
+    5, 0, 5, 35, 10, 5, 0, 113, 113, 20, 25, 5, 45, 0, 113, 0, 0, 0, 15, 30, 20, 25, 20, 113, 113,
+    20, 113, 0, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+    113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113, 113,
+];
+static RESERVED_LIST: [(&str, bool, bool, bool); 113] = [
+    ("", false, false, false),
+    ("~", true, false, false),
+    ("is", true, false, false),
+    ("...", true, false, false),
+    ("", false, false, false),
+    ("print", true, true, false),
+    ("@", true, false, false),
+    ("private", cfg!(feature = "no_function"), false, false),
+    ("", false, false, false),
+    ("this", true, false, false),
+    ("", false, false, false),
+    ("thread", true, false, false),
+    ("as", cfg!(feature = "no_module"), false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("spawn", true, false, false),
+    ("static", true, false, false),
+    (":=", true, false, false),
+    ("===", true, false, false),
+    ("case", true, false, false),
+    ("super", true, false, false),
+    ("shared", true, false, false),
+    ("package", true, false, false),
+    ("use", true, false, false),
+    ("with", true, false, false),
+    ("curry", true, true, true),
+    ("$", true, false, false),
+    ("type_of", true, true, true),
+    ("nil", true, false, false),
+    ("sync", true, false, false),
+    ("yield", true, false, false),
+    ("import", cfg!(feature = "no_module"), false, false),
+    ("--", true, false, false),
+    ("new", true, false, false),
+    ("exit", true, false, false),
+    ("async", true, false, false),
+    ("export", cfg!(feature = "no_module"), false, false),
+    ("!.", true, false, false),
+    ("", false, false, false),
+    ("call", true, true, true),
+    ("match", true, false, false),
+    ("", false, false, false),
+    ("fn", cfg!(feature = "no_function"), false, false),
+    ("var", true, false, false),
+    ("null", true, false, false),
+    ("await", true, false, false),
+    ("#", true, false, false),
+    ("default", true, false, false),
+    ("!==", true, false, false),
+    ("eval", true, true, false),
+    ("debug", true, true, false),
+    ("?", true, false, false),
+    ("?.", cfg!(feature = "no_object"), false, false),
+    ("", false, false, false),
+    ("protected", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("go", true, false, false),
+    ("", false, false, false),
+    ("goto", true, false, false),
+    ("", false, false, false),
+    ("public", true, false, false),
+    ("<-", true, false, false),
+    ("", false, false, false),
+    ("is_def_fn", cfg!(not(feature = "no_function")), true, false),
+    ("is_def_var", true, true, false),
+    ("", false, false, false),
+    ("<|", true, false, false),
+    ("::<", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("->", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("module", true, false, false),
+    ("|>", true, false, false),
+    ("", false, false, false),
+    ("void", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("#!", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("?[", cfg!(feature = "no_index"), false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("Fn", true, true, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    (":;", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("++", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("*)", true, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("", false, false, false),
+    ("(*", true, false, false),
+];
+
 impl Token {
     /// Is the token a literal symbol?
     #[must_use]
@@ -529,101 +868,38 @@ impl Token {
     }
 
     /// Reverse lookup a symbol token from a piece of syntax.
+    #[inline]
     #[must_use]
     pub fn lookup_symbol_from_syntax(syntax: &str) -> Option<Self> {
-        #[allow(clippy::enum_glob_use)]
+        // This implementation is based upon a pre-calculated table generated
-        use Token::*;
+        // by GNU gperf on the list of keywords.
+        let utf8 = syntax.as_bytes();
+        let len = utf8.len();
+        let mut hash_val = len;
 
-        Some(match syntax {
+        if !(MIN_KEYWORD_LEN..=MAX_KEYWORD_LEN).contains(&len) {
-            "{" => LeftBrace,
+            return None;
-            "}" => RightBrace,
+        }
-            "(" => LeftParen,
-            ")" => RightParen,
-            "[" => LeftBracket,
-            "]" => RightBracket,
-            "()" => Unit,
-            "+" => Plus,
-            "-" => Minus,
-            "*" => Multiply,
-            "/" => Divide,
-            ";" => SemiColon,
-            ":" => Colon,
-            "::" => DoubleColon,
-            "=>" => DoubleArrow,
-            "_" => Underscore,
-            "," => Comma,
-            "." => Period,
-            #[cfg(not(feature = "no_object"))]
-            "?." => Elvis,
-            "??" => DoubleQuestion,
-            #[cfg(not(feature = "no_index"))]
-            "?[" => QuestionBracket,
-            ".." => ExclusiveRange,
-            "..=" => InclusiveRange,
-            "#{" => MapStart,
-            "=" => Equals,
-            "true" => True,
-            "false" => False,
-            "let" => Let,
-            "const" => Const,
-            "if" => If,
-            "else" => Else,
-            "switch" => Switch,
-            "do" => Do,
-            "while" => While,
-            "until" => Until,
-            "loop" => Loop,
-            "for" => For,
-            "in" => In,
-            "!in" => NotIn,
-            "<" => LessThan,
-            ">" => GreaterThan,
-            "!" => Bang,
-            "<=" => LessThanEqualsTo,
-            ">=" => GreaterThanEqualsTo,
-            "==" => EqualsTo,
-            "!=" => NotEqualsTo,
-            "|" => Pipe,
-            "||" => Or,
-            "&" => Ampersand,
-            "&&" => And,
-            "continue" => Continue,
-            "break" => Break,
-            "return" => Return,
-            "throw" => Throw,
-            "try" => Try,
-            "catch" => Catch,
-            "+=" => PlusAssign,
-            "-=" => MinusAssign,
-            "*=" => MultiplyAssign,
-            "/=" => DivideAssign,
-            "<<=" => LeftShiftAssign,
-            ">>=" => RightShiftAssign,
-            "&=" => AndAssign,
-            "|=" => OrAssign,
-            "^=" => XOrAssign,
-            "<<" => LeftShift,
-            ">>" => RightShift,
-            "^" => XOr,
-            "%" => Modulo,
-            "%=" => ModuloAssign,
-            "**" => PowerOf,
-            "**=" => PowerOfAssign,
 
-            #[cfg(not(feature = "no_function"))]
+        match len {
-            "fn" => Fn,
+            1 => (),
-            #[cfg(not(feature = "no_function"))]
+            _ => hash_val += KEYWORD_ASSOC_VALUES[(utf8[1] as usize) + 1] as usize,
-            "private" => Private,
+        }
+        hash_val += KEYWORD_ASSOC_VALUES[utf8[0] as usize] as usize;
 
-            #[cfg(not(feature = "no_module"))]
+        if !(MIN_KEYWORD_HASH_VALUE..=MAX_KEYWORD_HASH_VALUE).contains(&hash_val) {
-            "import" => Import,
+            return None;
-            #[cfg(not(feature = "no_module"))]
+        }
-            "export" => Export,
-            #[cfg(not(feature = "no_module"))]
-            "as" => As,
 
-            _ => return None,
+        match KEYWORDS_LIST[hash_val] {
-        })
+            (_, Token::EOF) => None,
+            // Fail early to avoid calling memcmp()
+            // Since we are already working with bytes, mind as well check the first one
+            (s, ref t) if s.len() == len && s.as_bytes()[0] == utf8[0] && s == syntax => {
+                Some(t.clone())
+            }
+            _ => None,
+        }
     }
 
     /// If another operator is after these, it's probably a unary operator
@@ -932,7 +1208,7 @@ pub fn parse_string_literal(
     }
 
     loop {
-        assert!(
+        debug_assert!(
             !verbatim || escape.is_empty(),
             "verbatim strings should not have any escapes"
         );
@@ -1229,11 +1505,7 @@ fn get_next_token_inner(
     // Still inside a comment?
     if state.comment_level > 0 {
         let start_pos = *pos;
-        let mut comment = if state.include_comments {
+        let mut comment = state.include_comments.then(|| String::new());
-            Some(String::new())
-        } else {
-            None
-        };
 
         state.comment_level =
             scan_block_comment(stream, state.comment_level, pos, comment.as_mut());
@@ -1273,8 +1545,10 @@ fn get_next_token_inner(
         pos.advance();
 
         let start_pos = *pos;
+        let cc = stream.peek_next().unwrap_or('\0');
 
-        match (c, stream.peek_next().unwrap_or('\0')) {
+        // Identifiers and strings that can have non-ASCII characters
+        match (c, cc) {
             // \n
             ('\n', ..) => pos.new_line(),
 
@@ -1438,16 +1712,6 @@ fn get_next_token_inner(
                 return Some((token, num_pos));
             }
 
-            // letter or underscore ...
-            #[cfg(not(feature = "unicode-xid-ident"))]
-            ('a'..='z' | '_' | 'A'..='Z', ..) => {
-                return Some(parse_identifier_token(stream, state, pos, start_pos, c));
-            }
-            #[cfg(feature = "unicode-xid-ident")]
-            (ch, ..) if unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' => {
-                return Some(parse_identifier_token(stream, state, pos, start_pos, c));
-            }
-
             // " - string literal
             ('"', ..) => {
                 return parse_string_literal(stream, state, pos, c, false, true, false)
@@ -1919,11 +2183,16 @@ fn get_next_token_inner(
             }
             ('?', ..) => return Some((Token::Reserved(Box::new("?".into())), start_pos)),
 
-            (ch, ..) if ch.is_whitespace() => (),
+            // letter or underscore ...
+            _ if is_id_first_alphabetic(c) || c == '_' => {
+                return Some(parse_identifier_token(stream, state, pos, start_pos, c));
+            }
 
-            (ch, ..) => {
+            _ if c.is_whitespace() => (),
+
+            _ => {
                 return Some((
-                    Token::LexError(LERR::UnexpectedInput(ch.to_string()).into()),
+                    Token::LexError(LERR::UnexpectedInput(c.to_string()).into()),
                     start_pos,
                 ))
             }
@@ -1967,7 +2236,7 @@ fn parse_identifier_token(
         return (token, start_pos);
     }
 
-    if is_reserved_keyword_or_symbol(&identifier) {
+    if is_reserved_keyword_or_symbol(&identifier).0 {
         return (Token::Reserved(Box::new(identifier)), start_pos);
     }
 
@@ -1981,30 +2250,6 @@ fn parse_identifier_token(
     (Token::Identifier(identifier.into()), start_pos)
 }
 
-/// Can a keyword be called like a function?
-///
-/// # Return values
-///
-/// The first `bool` indicates whether the keyword can be called normally as a function.
-///
-/// The second `bool` indicates whether the keyword can be called in method-call style.
-#[inline]
-#[must_use]
-pub fn is_keyword_function(name: &str) -> (bool, bool) {
-    match name {
-        KEYWORD_TYPE_OF | KEYWORD_FN_PTR_CALL | KEYWORD_FN_PTR_CURRY => (true, true),
-
-        KEYWORD_PRINT | KEYWORD_DEBUG | KEYWORD_EVAL | KEYWORD_FN_PTR | KEYWORD_IS_DEF_VAR => {
-            (true, false)
-        }
-
-        #[cfg(not(feature = "no_function"))]
-        crate::engine::KEYWORD_IS_DEF_FN => (true, false),
-
-        _ => (false, false),
-    }
-}
-
 /// _(internals)_ Is a text string a valid identifier?
 /// Exported under the `internals` feature only.
 #[must_use]
@@ -2030,72 +2275,71 @@ pub fn is_valid_identifier(name: &str) -> bool {
 #[must_use]
 pub fn is_valid_function_name(name: &str) -> bool {
     is_valid_identifier(name)
-        && !is_reserved_keyword_or_symbol(name)
+        && !is_reserved_keyword_or_symbol(name).0
         && Token::lookup_symbol_from_syntax(name).is_none()
 }
 
 /// Is a character valid to start an identifier?
-#[cfg(feature = "unicode-xid-ident")]
 #[inline(always)]
 #[must_use]
 pub fn is_id_first_alphabetic(x: char) -> bool {
-    unicode_xid::UnicodeXID::is_xid_start(x)
+    #[cfg(feature = "unicode-xid-ident")]
+    return unicode_xid::UnicodeXID::is_xid_start(x);
+    #[cfg(not(feature = "unicode-xid-ident"))]
+    return x.is_ascii_alphabetic();
 }
 
 /// Is a character valid for an identifier?
-#[cfg(feature = "unicode-xid-ident")]
 #[inline(always)]
 #[must_use]
 pub fn is_id_continue(x: char) -> bool {
-    unicode_xid::UnicodeXID::is_xid_continue(x)
+    #[cfg(feature = "unicode-xid-ident")]
+    return unicode_xid::UnicodeXID::is_xid_continue(x);
+    #[cfg(not(feature = "unicode-xid-ident"))]
+    return x.is_ascii_alphanumeric() || x == '_';
 }
 
-/// Is a character valid to start an identifier?
+/// Is a piece of syntax a reserved keyword or reserved symbol?
-#[cfg(not(feature = "unicode-xid-ident"))]
+///
-#[inline(always)]
+/// # Return values
+///
+/// The first `bool` indicates whether it is a reserved keyword or symbol.
+///
+/// The second `bool` indicates whether the keyword can be called normally as a function.
+///
+/// The third `bool` indicates whether the keyword can be called in method-call style.
+#[inline]
 #[must_use]
-pub const fn is_id_first_alphabetic(x: char) -> bool {
+pub fn is_reserved_keyword_or_symbol(syntax: &str) -> (bool, bool, bool) {
-    x.is_ascii_alphabetic()
+    // This implementation is based upon a pre-calculated table generated
-}
+    // by GNU gperf on the list of keywords.
+    let utf8 = syntax.as_bytes();
+    let len = utf8.len();
+    let rounds = len.min(3);
+    let mut hash_val = len;
 
-/// Is a character valid for an identifier?
+    if !(MIN_RESERVED_LEN..=MAX_RESERVED_LEN).contains(&len) {
-#[cfg(not(feature = "unicode-xid-ident"))]
+        return (false, false, false);
-#[inline(always)]
+    }
-#[must_use]
-pub const fn is_id_continue(x: char) -> bool {
-    x.is_ascii_alphanumeric() || x == '_'
-}
 
-/// Is a piece of syntax a reserved keyword or symbol?
+    for x in 0..rounds {
-#[must_use]
+        hash_val += RESERVED_ASSOC_VALUES[utf8[rounds - 1 - x] as usize] as usize;
-pub fn is_reserved_keyword_or_symbol(syntax: &str) -> bool {
+    }
-    match syntax {
-        #[cfg(feature = "no_object")]
-        "?." => true,
-        #[cfg(feature = "no_index")]
-        "?[" => true,
-        #[cfg(feature = "no_function")]
-        "fn" | "private" => true,
-        #[cfg(feature = "no_module")]
-        "import" | "export" | "as" => true,
 
-        // List of reserved operators
+    if !(MIN_RESERVED_HASH_VALUE..=MAX_RESERVED_HASH_VALUE).contains(&hash_val) {
-        "===" | "!==" | "->" | "<-" | "?" | ":=" | ":;" | "~" | "!." | "::<" | "(*" | "*)"
+        return (false, false, false);
-        | "#" | "#!" | "@" | "$" | "++" | "--" | "..." | "<|" | "|>" => true,
+    }
 
-        // List of reserved keywords
+    match RESERVED_LIST[hash_val] {
-        "public" | "protected" | "super" | "new" | "use" | "module" | "package" | "var"
+        ("", ..) => (false, false, false),
-        | "static" | "shared" | "with" | "is" | "goto" | "exit" | "match" | "case" | "default"
+        (s, true, a, b) => (
-        | "void" | "null" | "nil" | "spawn" | "thread" | "go" | "sync" | "async" | "await"
+            // Fail early to avoid calling memcmp()
-        | "yield" => true,
+            // Since we are already working with bytes, mind as well check the first one
-
+            s.len() == len && s.as_bytes()[0] == utf8[0] && s == syntax,
-        KEYWORD_PRINT | KEYWORD_DEBUG | KEYWORD_TYPE_OF | KEYWORD_EVAL | KEYWORD_FN_PTR
+            a,
-        | KEYWORD_FN_PTR_CALL | KEYWORD_FN_PTR_CURRY | KEYWORD_THIS | KEYWORD_IS_DEF_VAR => true,
+            b,
-
+        ),
-        #[cfg(not(feature = "no_function"))]
+        _ => (false, false, false),
-        crate::engine::KEYWORD_IS_DEF_FN => true,
-
-        _ => false,
     }
 }
 

src/tools/README.md

@@ -0,0 +1,7 @@
+Build Tools
+===========
+
+| File           | Description                                 |
+| -------------- | ------------------------------------------- |
+| `keywords.txt` | Input file for GNU gperf for the tokenizer. |
+| `reserved.txt` | Input file for GNU gperf for the tokenizer. |

src/tools/keywords.txt

@@ -0,0 +1,102 @@
+// This file holds a list of keywords/symbols for the Rhai language, with mapping to
+// an appropriate `Token` variant.
+//
+// Generate the output table via:
+// ```bash
+// gperf -t keywords.txt
+// ```
+//
+// Since GNU gperf does not produce Rust output, the ANSI-C output must be hand-edited and
+// manually spliced into `tokenizer.rs`.
+//
+// This includes:
+// * Rewrite the C hashing program (especially since it uses a `switch` statement with fall-through)
+//   into equivalent Rust as the function `lookup_symbol_from_syntax`.
+// * Update the values for the `???_KEYWORD_???` constants.
+// * Copy the `asso_values` array into `KEYWORD_ASSOC_VALUES`.
+// * Copy the `wordlist` array into `KEYWORDS_LIST` with the following modifications:
+//   - Remove the `#line` comments
+//   - Change the entry wrapping `{ .. }` into tuples `( .. )`
+//   - Replace all entries `("")` by `("", Token::EOF)`
+//   - Put feature flags on the appropriate lines, and duplicating lines that maps to `Token::EOF`
+//     for the opposite feature flags
+//
+struct keyword;
+%%
+"{",        Token::LeftBrace
+"}",        Token::RightBrace
+"(",        Token::LeftParen
+")",        Token::RightParen
+"[",        Token::LeftBracket
+"]",        Token::RightBracket
+"()",       Token::Unit
+"+",        Token::Plus
+"-",        Token::Minus
+"*",        Token::Multiply
+"/",        Token::Divide
+";",        Token::SemiColon
+":",        Token::Colon
+"::",       Token::DoubleColon
+"=>",       Token::DoubleArrow
+"_",        Token::Underscore
+",",        Token::Comma
+".",        Token::Period
+"?.",       Token::Elvis
+"??",       Token::DoubleQuestion
+"?[",       Token::QuestionBracket
+"..",       Token::ExclusiveRange
+"..=",      Token::InclusiveRange
+"#{",       Token::MapStart
+"=",        Token::Equals
+"true",     Token::True
+"false",    Token::False
+"let",      Token::Let
+"const",    Token::Const
+"if",       Token::If
+"else",     Token::Else
+"switch",   Token::Switch
+"do",       Token::Do
+"while",    Token::While
+"until",    Token::Until
+"loop",     Token::Loop
+"for",      Token::For
+"in",       Token::In
+"!in",      Token::NotIn
+"<",        Token::LessThan
+">",        Token::GreaterThan
+"<=",       Token::LessThanEqualsTo
+">=",       Token::GreaterThanEqualsTo
+"==",       Token::EqualsTo
+"!=",       Token::NotEqualsTo
+"!",        Token::Bang
+"|",        Token::Pipe
+"||",       Token::Or
+"&",        Token::Ampersand
+"&&",       Token::And
+"continue", Token::Continue
+"break",    Token::Break
+"return",   Token::Return
+"throw",    Token::Throw
+"try",      Token::Try
+"catch",    Token::Catch
+"+=",       Token::PlusAssign
+"-=",       Token::MinusAssign
+"*=",       Token::MultiplyAssign
+"/=",       Token::DivideAssign
+"<<=",      Token::LeftShiftAssign
+">>=",      Token::RightShiftAssign
+"&=",       Token::AndAssign
+"|=",       Token::OrAssign
+"^=",       Token::XOrAssign
+"<<",       Token::LeftShift
+">>",       Token::RightShift
+"^",        Token::XOr
+"%",        Token::Modulo
+"%=",       Token::ModuloAssign
+"**",       Token::PowerOf
+"**=",      Token::PowerOfAssign
+"fn",       Token::Fn
+"private",  Token::Private
+"import",   Token::Import
+"export",   Token::Export
+"as",       Token::As

src/tools/reserved.txt

@@ -0,0 +1,93 @@
+// This file holds a list of reserved symbols for the Rhai language.
+//
+// The mapped attributes are:
+// - is this a reserved symbol? (bool)
+// - can this keyword be called normally as a function? (bool)
+// - can this keyword be called in method-call style? (bool)
+//
+// Generate the output table via:
+// ```bash
+// gperf -t reserved.txt
+// ```
+//
+// Since GNU gperf does not produce Rust output, the ANSI-C output must be hand-edited and
+// manually spliced into `tokenizer.rs`.
+//
+// This includes:
+// * Rewrite the C hashing program (especially since it uses a `switch` statement with fall-through)
+//   into equivalent Rust as the function `is_reserved_keyword_or_symbol`.
+// * Update the values for the `???_RESERVED_???` constants.
+// * Copy the `asso_values` array into `RESERVED_ASSOC_VALUES`.
+// * Copy the `wordlist` array into `RESERVED_LIST` with the following modifications:
+//   - Remove the `#line` comments
+//   - Change the entry wrapping `{ .. }` into tuples `( .. )`
+//   - Replace all entries `("")` by `("", false, false, false)`
+//   - Feature flags can be incorporated directly into the output via the `cfg!` macro
+//
+struct reserved;
+%%
+"?.",           cfg!(feature = "no_object"), false, false
+"?[",           cfg!(feature = "no_index"), false, false
+"fn",           cfg!(feature = "no_function"), false, false
+"private",      cfg!(feature = "no_function"), false, false
+"import",       cfg!(feature = "no_module"), false, false
+"export",       cfg!(feature = "no_module"), false, false
+"as",           cfg!(feature = "no_module"), false, false
+"===",          true, false, false
+"!==",          true, false, false
+"->",           true, false, false
+"<-",           true, false, false
+"?",            true, false, false
+":=",           true, false, false
+":;",           true, false, false
+"~",            true, false, false
+"!.",           true, false, false
+"::<",          true, false, false
+"(*",           true, false, false
+"*)",           true, false, false
+"#",            true, false, false
+"#!",           true, false, false
+"@",            true, false, false
+"$",            true, false, false
+"++",           true, false, false
+"--",           true, false, false
+"...",          true, false, false
+"<|",           true, false, false
+"|>",           true, false, false
+"public",       true, false, false
+"protected",    true, false, false
+"super",        true, false, false
+"new",          true, false, false
+"use",          true, false, false
+"module",       true, false, false
+"package",      true, false, false
+"var",          true, false, false
+"static",       true, false, false
+"shared",       true, false, false
+"with",         true, false, false
+"is",           true, false, false
+"goto",         true, false, false
+"exit",         true, false, false
+"match",        true, false, false
+"case",         true, false, false
+"default",      true, false, false
+"void",         true, false, false
+"null",         true, false, false
+"nil",          true, false, false
+"spawn",        true, false, false
+"thread",       true, false, false
+"go",           true, false, false
+"sync",         true, false, false
+"async",        true, false, false
+"await",        true, false, false
+"yield",        true, false, false
+"print",        true, true, false
+"debug",        true, true, false
+"type_of",      true, true, true
+"eval",         true, true, false
+"Fn",           true, true, false
+"call",         true, true, true
+"curry",        true, true, true
+"this",         true, false, false
+"is_def_var",   true, true, false
+"is_def_fn",    cfg!(not(feature = "no_function")), true, false

src/types/fn_ptr.rs

@@ -538,7 +538,7 @@ impl TryFrom<ImmutableString> for FnPtr {
                 #[cfg(not(feature = "no_function"))]
                 fn_def: None,
             })
-        } else if is_reserved_keyword_or_symbol(&value)
+        } else if is_reserved_keyword_or_symbol(&value).0
             || Token::lookup_symbol_from_syntax(&value).is_some()
         {
             Err(

src/types/parse_error.rs

@@ -105,7 +105,7 @@ pub enum ParseErrorType {
     DuplicatedSwitchCase,
     /// A variable name is duplicated. Wrapped value is the variable name.
     DuplicatedVariable(String),
-    /// An integer case of a `switch` statement is in an appropriate place.
+    /// A numeric case of a `switch` statement is in an appropriate place.
     WrongSwitchIntegerCase,
     /// The default case of a `switch` statement is in an appropriate place.
     WrongSwitchDefaultCase,
@@ -236,7 +236,7 @@ impl fmt::Display for ParseErrorType {
             Self::Reserved(s) if is_valid_identifier(s.as_str()) => write!(f, "'{s}' is a reserved keyword"),
             Self::Reserved(s) => write!(f, "'{s}' is a reserved symbol"),
             Self::UnexpectedEOF => f.write_str("Script is incomplete"),
-            Self::WrongSwitchIntegerCase => f.write_str("Integer switch case cannot follow a range case"),
+            Self::WrongSwitchIntegerCase => f.write_str("Numeric switch case cannot follow a range case"),
             Self::WrongSwitchDefaultCase => f.write_str("Default switch case must be the last"),
             Self::WrongSwitchCaseCondition => f.write_str("This switch case cannot have a condition"),
             Self::PropertyExpected => f.write_str("Expecting name of a property"),

src/types/scope.rs

@@ -385,11 +385,23 @@ impl Scope<'_> {
     /// ```
     #[inline(always)]
     pub fn pop(&mut self) -> &mut Self {
-        self.names.pop().expect("`Scope` must not be empty");
+        self.names.pop().expect("not empty");
-        let _ = self.values.pop().expect("`Scope` must not be empty");
+        let _ = self.values.pop().expect("not empty");
-        self.aliases.pop().expect("`Scope` must not be empty");
+        self.aliases.pop().expect("not empty");
         self
     }
+    /// Remove the last entry from the [`Scope`] and return it.
+    #[inline(always)]
+    #[allow(dead_code)]
+    pub(crate) fn pop_entry(&mut self) -> Option<(Identifier, Dynamic, Vec<ImmutableString>)> {
+        self.values.pop().map(|value| {
+            (
+                self.names.pop().expect("not empty"),
+                value,
+                self.aliases.pop().expect("not empty"),
+            )
+        })
+    }
     /// Truncate (rewind) the [`Scope`] to a previous size.
     ///
     /// # Example

tests/arrays.rs

@@ -515,14 +515,12 @@ fn test_arrays_map_reduce() -> Result<(), Box<EvalAltResult>> {
         3
     );
 
-    engine
+    engine.eval::<()>(
-        .eval::<()>(
+        "
-            "
                 let x = [1, 2, 3, 2, 1];
                 x.find(|v| v > 4)
             ",
-        )
+    )?;
-        .unwrap();
 
     assert_eq!(
         engine.eval::<INT>(
@@ -534,14 +532,12 @@ fn test_arrays_map_reduce() -> Result<(), Box<EvalAltResult>> {
         2
     );
 
-    engine
+    engine.eval::<()>(
-        .eval::<()>(
+        "
-            "
                 let x = [#{alice: 1}, #{bob: 2}, #{clara: 3}];
                 x.find_map(|v| v.dave)
             ",
-        )
+    )?;
-        .unwrap();
 
     Ok(())
 }
@@ -550,7 +546,7 @@ fn test_arrays_map_reduce() -> Result<(), Box<EvalAltResult>> {
 fn test_arrays_elvis() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    engine.eval::<()>("let x = (); x?[2]").unwrap();
+    engine.eval::<()>("let x = (); x?[2]")?;
 
     engine.run("let x = (); x?[2] = 42")?;
 

tests/bool_op.rs

@@ -4,8 +4,8 @@ use rhai::{Engine, EvalAltResult};
 fn test_bool_op1() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    assert!(engine.eval::<bool>("true && (false || true)").unwrap());
+    assert!(engine.eval::<bool>("true && (false || true)")?);
-    assert!(engine.eval::<bool>("true & (false | true)").unwrap());
+    assert!(engine.eval::<bool>("true & (false | true)")?);
 
     Ok(())
 }
@@ -14,8 +14,8 @@ fn test_bool_op1() -> Result<(), Box<EvalAltResult>> {
 fn test_bool_op2() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    assert!(!engine.eval::<bool>("false && (false || true)").unwrap());
+    assert!(!engine.eval::<bool>("false && (false || true)")?);
-    assert!(!engine.eval::<bool>("false & (false | true)").unwrap());
+    assert!(!engine.eval::<bool>("false & (false | true)")?);
 
     Ok(())
 }
@@ -25,9 +25,9 @@ fn test_bool_op3() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
     assert!(engine.eval::<bool>("true && (false || 123)").is_err());
-    assert!(engine.eval::<bool>("true && (true || { throw })").unwrap());
+    assert!(engine.eval::<bool>("true && (true || { throw })")?);
     assert!(engine.eval::<bool>("123 && (false || true)").is_err());
-    assert!(!engine.eval::<bool>("false && (true || { throw })").unwrap());
+    assert!(!engine.eval::<bool>("false && (true || { throw })")?);
 
     Ok(())
 }
@@ -36,23 +36,19 @@ fn test_bool_op3() -> Result<(), Box<EvalAltResult>> {
 fn test_bool_op_short_circuit() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    assert!(engine
+    assert!(engine.eval::<bool>(
-        .eval::<bool>(
+        "
-            "
                 let x = true;
                 x || { throw; };
             "
-        )
+    )?);
-        .unwrap());
 
-    assert!(!engine
+    assert!(!engine.eval::<bool>(
-        .eval::<bool>(
+        "
-            "
                 let x = false;
                 x && { throw; };
             "
-        )
+    )?);
-        .unwrap());
 
     Ok(())
 }

tests/closures.rs

@@ -369,9 +369,9 @@ fn test_closures_external() -> Result<(), Box<EvalAltResult>> {
 
     let fn_ptr = engine.eval_ast::<FnPtr>(&ast)?;
 
-    let f = move |x: INT| -> String { fn_ptr.call(&engine, &ast, (x,)).unwrap() };
+    let f = move |x: INT| fn_ptr.call::<String>(&engine, &ast, (x,));
 
-    assert_eq!(f(42), "hello42");
+    assert_eq!(f(42)?, "hello42");
 
     Ok(())
 }
@@ -383,20 +383,20 @@ fn test_closures_callback() -> Result<(), Box<EvalAltResult>> {
     type SingleNode = Rc<dyn Node>;
 
     trait Node {
-        fn run(&self, x: INT) -> INT;
+        fn run(&self, x: INT) -> Result<INT, Box<EvalAltResult>>;
     }
 
     struct PhaserNode {
-        func: Box<dyn Fn(INT) -> INT>,
+        func: Box<dyn Fn(INT) -> Result<INT, Box<EvalAltResult>>>,
     }
 
     impl Node for PhaserNode {
-        fn run(&self, x: INT) -> INT {
+        fn run(&self, x: INT) -> Result<INT, Box<EvalAltResult>> {
             (self.func)(x)
         }
     }
 
-    fn phaser(callback: impl Fn(INT) -> INT + 'static) -> impl Node {
+    fn phaser(callback: impl Fn(INT) -> Result<INT, Box<EvalAltResult>> + 'static) -> impl Node {
         PhaserNode {
             func: Box::new(callback),
         }
@@ -419,7 +419,7 @@ fn test_closures_callback() -> Result<(), Box<EvalAltResult>> {
         let engine = engine2.clone();
         let ast = ast2.clone();
 
-        let callback = Box::new(move |x: INT| fp.call(&engine.borrow(), &ast, (x,)).unwrap());
+        let callback = Box::new(move |x: INT| fp.call(&engine.borrow(), &ast, (x,)));
 
         Rc::new(phaser(callback)) as SingleNode
     });
@@ -428,7 +428,7 @@ fn test_closures_callback() -> Result<(), Box<EvalAltResult>> {
 
     let cb = shared_engine.borrow().eval_ast::<SingleNode>(&ast)?;
 
-    assert_eq!(cb.run(21), 42);
+    assert_eq!(cb.run(21)?, 42);
 
     Ok(())
 }

tests/comments.rs

@@ -21,7 +21,7 @@ fn test_comments() -> Result<(), Box<EvalAltResult>> {
         42
     );
 
-    engine.run("/* Hello world */").unwrap();
+    engine.run("/* Hello world */")?;
 
     Ok(())
 }

tests/compound_equality.rs

@@ -5,8 +5,8 @@ fn test_or_equals() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
     assert_eq!(engine.eval::<INT>("let x = 16; x |= 74; x")?, 90);
-    assert!(engine.eval::<bool>("let x = true; x |= false; x").unwrap());
+    assert!(engine.eval::<bool>("let x = true; x |= false; x")?);
-    assert!(engine.eval::<bool>("let x = false; x |= true; x").unwrap());
+    assert!(engine.eval::<bool>("let x = false; x |= true; x")?);
 
     Ok(())
 }
@@ -16,9 +16,9 @@ fn test_and_equals() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
     assert_eq!(engine.eval::<INT>("let x = 16; x &= 31; x")?, 16);
-    assert!(!engine.eval::<bool>("let x = true; x &= false; x").unwrap());
+    assert!(!engine.eval::<bool>("let x = true; x &= false; x")?);
-    assert!(!engine.eval::<bool>("let x = false; x &= true; x").unwrap());
+    assert!(!engine.eval::<bool>("let x = false; x &= true; x")?);
-    assert!(engine.eval::<bool>("let x = true; x &= true; x").unwrap());
+    assert!(engine.eval::<bool>("let x = true; x &= true; x")?);
 
     Ok(())
 }

tests/custom_syntax.rs

@@ -251,6 +251,62 @@ fn test_custom_syntax() -> Result<(), Box<EvalAltResult>> {
     Ok(())
 }
 
+#[test]
+fn test_custom_syntax_matrix() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    engine.disable_symbol("|");
+
+    engine.register_custom_syntax(
+        [
+            "@", //
+            "|", "$expr$", "$expr$", "$expr$", "|", //
+            "|", "$expr$", "$expr$", "$expr$", "|", //
+            "|", "$expr$", "$expr$", "$expr$", "|",
+        ],
+        false,
+        |context, inputs| {
+            let mut values = [[0; 3]; 3];
+
+            for y in 0..3 {
+                for x in 0..3 {
+                    let offset = y * 3 + x;
+
+                    match context.eval_expression_tree(&inputs[offset])?.as_int() {
+                        Ok(v) => values[y][x] = v,
+                        Err(typ) => {
+                            return Err(Box::new(EvalAltResult::ErrorMismatchDataType(
+                                "integer".to_string(),
+                                typ.to_string(),
+                                inputs[offset].position(),
+                            )))
+                        }
+                    }
+                }
+            }
+
+            Ok(Dynamic::from(values))
+        },
+    )?;
+
+    let r = engine.eval::<[[INT; 3]; 3]>(
+        "
+            let a = 42;
+            let b = 123;
+            let c = 1;
+            let d = 99;
+
+            @|  a   b   0  |
+             | -b   a   0  |
+             |  0   0  c*d |
+        ",
+    )?;
+
+    assert_eq!(r, [[42, 123, 0], [-123, 42, 0], [0, 0, 99]]);
+
+    Ok(())
+}
+
 #[test]
 fn test_custom_syntax_raw() -> Result<(), Box<EvalAltResult>> {
     let mut engine = Engine::new();

tests/expressions.rs

@@ -50,8 +50,8 @@ fn test_expressions() -> Result<(), Box<EvalAltResult>> {
             "
                 switch x {
                     0 => 1,
-                    1..10 => 123,
                     10 => 42,
+                    1..10 => 123,
                 }
             "
         )?,
@@ -63,11 +63,11 @@ fn test_expressions() -> Result<(), Box<EvalAltResult>> {
             "
                 switch x {
                     0 => 1,
+                    10 => 42,
                     1..10 => {
                         let y = 123;
                         y
                     }
-                    10 => 42,
                 }
             "
         )

tests/float.rs

@@ -9,9 +9,7 @@ fn test_float() -> Result<(), Box<EvalAltResult>> {
 
     assert!(engine.eval::<bool>("let x = 0.0; let y = 1.0; x < y")?);
     assert!(!engine.eval::<bool>("let x = 0.0; let y = 1.0; x > y")?);
-    assert!(!engine
+    assert!(!engine.eval::<bool>("let x = 0.; let y = 1.; x > y")?);
-        .eval::<bool>("let x = 0.; let y = 1.; x > y")
-        .unwrap());
     assert!((engine.eval::<FLOAT>("let x = 9.9999; x")? - 9.9999 as FLOAT).abs() < EPSILON);
 
     Ok(())

tests/get_set.rs

@@ -399,11 +399,9 @@ fn test_get_set_indexer() -> Result<(), Box<EvalAltResult>> {
 fn test_get_set_elvis() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    engine.eval::<()>("let x = (); x?.foo.bar.baz").unwrap();
+    engine.eval::<()>("let x = (); x?.foo.bar.baz")?;
-    engine.eval::<()>("let x = (); x?.foo(1,2,3)").unwrap();
+    engine.eval::<()>("let x = (); x?.foo(1,2,3)")?;
-    engine
+    engine.eval::<()>("let x = #{a:()}; x.a?.foo.bar.baz")?;
-        .eval::<()>("let x = #{a:()}; x.a?.foo.bar.baz")
-        .unwrap();
     assert_eq!(engine.eval::<String>("let x = 'x'; x?.type_of()")?, "char");
 
     Ok(())

tests/looping.rs

@@ -20,7 +20,7 @@ fn test_loop() -> Result<(), Box<EvalAltResult>> {
 					}
 				}
 
-				return x;
+				x
 		    "
         )?,
         21
@@ -53,3 +53,43 @@ fn test_loop() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_loop_expression() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    assert_eq!(
+        engine.eval::<INT>(
+            "
+				let x = 0;
+
+				let value = while x < 10 {
+                    if x % 5 == 0 { break 42; }
+                    x += 1;
+				};
+
+				value
+		    "
+        )?,
+        42
+    );
+
+    engine.set_allow_loop_expressions(false);
+
+    assert!(engine
+        .eval::<INT>(
+            "
+				let x = 0;
+
+				let value = while x < 10 {
+                    if x % 5 == 0 { break 42; }
+                    x += 1;
+				};
+
+				value
+		    "
+        )
+        .is_err());
+
+    Ok(())
+}

tests/mismatched_op.rs

@@ -39,7 +39,10 @@ fn test_mismatched_op_custom_type() -> Result<(), Box<EvalAltResult>> {
         ").expect_err("should error"),
         EvalAltResult::ErrorFunctionNotFound(f, ..) if f == "== (TestStruct, TestStruct)"));
 
-    assert!(!engine.eval::<bool>("new_ts() == 42")?);
+    assert!(
+        matches!(*engine.eval::<bool>("new_ts() == 42").expect_err("should error"),
+        EvalAltResult::ErrorFunctionNotFound(f, ..) if f.starts_with("== (TestStruct, "))
+    );
 
     assert!(matches!(
         *engine.eval::<INT>("60 + new_ts()").expect_err("should error"),

tests/not.rs

@@ -4,14 +4,12 @@ use rhai::{Engine, EvalAltResult};
 fn test_not() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
-    assert!(!engine
+    assert!(!engine.eval::<bool>("let not_true = !true; not_true")?);
-        .eval::<bool>("let not_true = !true; not_true")
-        .unwrap());
 
     #[cfg(not(feature = "no_function"))]
-    assert!(engine.eval::<bool>("fn not(x) { !x } not(false)").unwrap());
+    assert!(engine.eval::<bool>("fn not(x) { !x } not(false)")?);
 
-    assert!(engine.eval::<bool>("!!!!true").unwrap());
+    assert!(engine.eval::<bool>("!!!!true")?);
 
     Ok(())
 }

tests/ops.rs

@@ -35,7 +35,11 @@ fn test_ops_other_number_types() -> Result<(), Box<EvalAltResult>> {
         EvalAltResult::ErrorFunctionNotFound(f, ..) if f.starts_with("== (u16,")
     ));
 
-    assert!(!engine.eval_with_scope::<bool>(&mut scope, r#"x == "hello""#)?);
+    assert!(
+        matches!(*engine.eval_with_scope::<bool>(&mut scope, r#"x == "hello""#).expect_err("should error"),
+            EvalAltResult::ErrorFunctionNotFound(f, ..) if f.starts_with("== (u16,")
+        )
+    );
 
     Ok(())
 }
@@ -63,3 +67,24 @@ fn test_ops_precedence() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_ops_custom_types() -> Result<(), Box<EvalAltResult>> {
+    #[derive(Debug, Clone, PartialEq, Eq)]
+    struct Test1;
+    #[derive(Debug, Clone, PartialEq, Eq)]
+    struct Test2;
+
+    let mut engine = Engine::new();
+
+    engine
+        .register_type_with_name::<Test1>("Test1")
+        .register_type_with_name::<Test2>("Test2")
+        .register_fn("new_ts1", || Test1)
+        .register_fn("new_ts2", || Test2)
+        .register_fn("==", |x: Test1, y: Test2| true);
+
+    assert!(engine.eval::<bool>("let x = new_ts1(); let y = new_ts2(); x == y")?);
+
+    Ok(())
+}

tests/optimizer.rs

@@ -89,21 +89,21 @@ fn test_optimizer_parse() -> Result<(), Box<EvalAltResult>> {
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [Expr(123 @ 1:53)] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [Expr(123 @ 1:53)] }"#
     );
 
     let ast = engine.compile("const DECISION = false; if DECISION { 42 } else { 123 }")?;
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [Var(("DECISION" @ 1:7, false @ 1:18, None), CONSTANT, 1:1), Expr(123 @ 1:51)] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [Var(("DECISION" @ 1:7, false @ 1:18, None), CONSTANT, 1:1), Expr(123 @ 1:51)] }"#
     );
 
     let ast = engine.compile("if 1 == 2 { 42 }")?;
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [] }"#
     );
 
     engine.set_optimization_level(OptimizationLevel::Full);
@@ -112,14 +112,14 @@ fn test_optimizer_parse() -> Result<(), Box<EvalAltResult>> {
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [Expr(42 @ 1:1)] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [Expr(42 @ 1:1)] }"#
     );
 
     let ast = engine.compile("NUMBER")?;
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [Expr(Variable(NUMBER) @ 1:1)] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [Expr(Variable(NUMBER) @ 1:1)] }"#
     );
 
     let mut module = Module::new();
@@ -131,7 +131,7 @@ fn test_optimizer_parse() -> Result<(), Box<EvalAltResult>> {
 
     assert_eq!(
         format!("{ast:?}"),
-        r#"AST { source: None, doc: "", resolver: None, body: [Expr(42 @ 1:1)] }"#
+        r#"AST { source: None, doc: None, resolver: None, body: [Expr(42 @ 1:1)] }"#
     );
 
     Ok(())

tests/switch.rs

@@ -10,9 +10,7 @@ fn test_switch() -> Result<(), Box<EvalAltResult>> {
         engine.eval::<char>("switch 2 { 1 => (), 2 => 'a', 42 => true }")?,
         'a'
     );
-    engine
+    engine.run("switch 3 { 1 => (), 2 => 'a', 42 => true }")?;
-        .run("switch 3 { 1 => (), 2 => 'a', 42 => true }")
-        .unwrap();
     assert_eq!(
         engine.eval::<INT>("switch 3 { 1 => (), 2 => 'a', 42 => true, _ => 123 }")?,
         123
@@ -31,15 +29,13 @@ fn test_switch() -> Result<(), Box<EvalAltResult>> {
         )?,
         'a'
     );
-    assert!(engine
+    assert!(
-        .eval_with_scope::<bool>(&mut scope, "switch x { 1 => (), 2 => 'a', 42 => true }")
+        engine.eval_with_scope::<bool>(&mut scope, "switch x { 1 => (), 2 => 'a', 42 => true }")?
-        .unwrap());
+    );
-    assert!(engine
+    assert!(
-        .eval_with_scope::<bool>(&mut scope, "switch x { 1 => (), 2 => 'a', _ => true }")
+        engine.eval_with_scope::<bool>(&mut scope, "switch x { 1 => (), 2 => 'a', _ => true }")?
-        .unwrap());
+    );
-    let _: () = engine
+    let _: () = engine.eval_with_scope::<()>(&mut scope, "switch x { 1 => 123, 2 => 'a' }")?;
-        .eval_with_scope::<()>(&mut scope, "switch x { 1 => 123, 2 => 'a' }")
-        .unwrap();
 
     assert_eq!(
         engine.eval_with_scope::<INT>(
@@ -276,6 +272,13 @@ fn test_switch_ranges() -> Result<(), Box<EvalAltResult>> {
         ).expect_err("should error").err_type(),
         ParseErrorType::WrongSwitchIntegerCase
     ));
+    #[cfg(not(feature = "no_float"))]
+    assert!(matches!(
+        engine.compile(
+            "switch x { 10..20 => (), 20..=42 => 'a', 25..45 => 'z', 42.0 => 'x', 30..100 => true }"
+        ).expect_err("should error").err_type(),
+        ParseErrorType::WrongSwitchIntegerCase
+    ));
     assert_eq!(
         engine.eval_with_scope::<char>(
             &mut scope,

tests/unit.rs

@@ -10,9 +10,7 @@ fn test_unit() -> Result<(), Box<EvalAltResult>> {
 #[test]
 fn test_unit_eq() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
-    assert!(engine
+    assert!(engine.eval::<bool>("let x = (); let y = (); x == y")?);
-        .eval::<bool>("let x = (); let y = (); x == y")
-        .unwrap());
     Ok(())
 }