Support compiling to WASM.

README.md

@@ -28,6 +28,7 @@ Features
 * Rugged - protection against malicious attacks (such as [stack-overflow](#maximum-call-stack-depth), [over-sized data](#maximum-length-of-strings), and [runaway scripts](#maximum-number-of-operations) etc.) that may come from untrusted third-party user-land scripts.
 * Track script evaluation [progress](#tracking-progress-and-force-terminate-script-run) and manually terminate a script run.
 * [`no-std`](#optional-features) support.
+* Supports compiling to `WASM`, optionally with [minimal builds](#minimal-builds).
 * [Function overloading](#function-overloading).
 * [Operator overloading](#operator-overloading).
 * Organize code base with dynamically-loadable [modules].
@@ -141,8 +142,8 @@ Making [`Dynamic`] small helps performance due to better cache efficiency.
 
 ### Minimal builds
 
-In order to compile a _minimal_build - i.e. a build optimized for size - perhaps for embedded targets, it is essential that
+In order to compile a _minimal_build - i.e. a build optimized for size - perhaps for `no-std` embedded targets or for
-the correct linker flags are used in `cargo.toml`:
+compiling to `WASM`, it is essential that the correct linker flags are used in `cargo.toml`:
 
 ```toml
 [profile.release]
@@ -156,7 +157,9 @@ all code is compiled in as what a script requires cannot be predicted. If a lang
 omitting them via special features is a prudent strategy to optimize the build for size.
 
 Omitting arrays (`no_index`) yields the most code-size savings, followed by floating-point support
-(`no_float`), checked arithmetic (`unchecked`) and finally object maps and custom types (`no_object`).
+(`no_float`), checked arithmetic/script resource limits (`unchecked`) and finally object maps and custom types (`no_object`).
+
+Where the usage scenario does not call for loading externally-defined modules, use `no_module` to save some bytes.
 Disable script-defined functions (`no_function`) only when the feature is not needed because code size savings is minimal.
 
 [`Engine::new_raw`](#raw-engine) creates a _raw_ engine.

RELEASES.md

@@ -23,7 +23,7 @@ New features
 * `Engine:register_fn` and `Engine:register_result_fn` accepts functions that take parameters of type `&str` (immutable string slice), which maps directly to `ImmutableString`. This is to avoid needing wrappers for functions taking string parameters.
 * Set maximum limit on data sizes: `Engine::set_max_string_size`, `Engine::set_max_array_size` and `Engine::set_max_map_size`.
 * Supports trailing commas on array literals, object map literals, function definitions and function calls.
-
+* Supports compiling to `WASM`.
 
 Version 0.15.0
 ==============

src/any.rs

@@ -24,6 +24,8 @@ use crate::stdlib::{
 };
 
 #[cfg(not(feature = "no_std"))]
+#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(target_arch = "wasm64"))]
 use crate::stdlib::time::Instant;
 
 /// Trait to represent any type.
@@ -192,6 +194,8 @@ impl Dynamic {
             Union::Module(_) => "sub-scope",
 
             #[cfg(not(feature = "no_std"))]
+            #[cfg(not(target_arch = "wasm32"))]
+            #[cfg(not(target_arch = "wasm64"))]
             Union::Variant(value) if value.is::<Instant>() => "timestamp",
             Union::Variant(value) => (***value).type_name(),
         }
@@ -215,6 +219,8 @@ impl fmt::Display for Dynamic {
             Union::Module(value) => fmt::Debug::fmt(value, f),
 
             #[cfg(not(feature = "no_std"))]
+            #[cfg(not(target_arch = "wasm32"))]
+            #[cfg(not(target_arch = "wasm64"))]
             Union::Variant(value) if value.is::<Instant>() => write!(f, "<timestamp>"),
             Union::Variant(_) => write!(f, "?"),
         }
@@ -238,6 +244,8 @@ impl fmt::Debug for Dynamic {
             Union::Module(value) => fmt::Debug::fmt(value, f),
 
             #[cfg(not(feature = "no_std"))]
+            #[cfg(not(target_arch = "wasm32"))]
+            #[cfg(not(target_arch = "wasm64"))]
             Union::Variant(value) if value.is::<Instant>() => write!(f, "<timestamp>"),
             Union::Variant(_) => write!(f, "<dynamic>"),
         }

src/api.rs

@@ -27,6 +27,8 @@ use crate::stdlib::{
 };
 
 #[cfg(not(feature = "no_std"))]
+#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(target_arch = "wasm64"))]
 use crate::stdlib::{fs::File, io::prelude::*, path::PathBuf};
 
 /// Engine public API

src/packages/pkg_std.rs

@@ -6,6 +6,8 @@ use super::math_basic::BasicMathPackage;
 use super::pkg_core::CorePackage;
 use super::string_more::MoreStringPackage;
 #[cfg(not(feature = "no_std"))]
+#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(target_arch = "wasm64"))]
 use super::time_basic::BasicTimePackage;
 
 use crate::def_package;
@@ -18,6 +20,8 @@ def_package!(crate:StandardPackage:"_Standard_ package containing all built-in f
     #[cfg(not(feature = "no_object"))]
     BasicMapPackage::init(lib);
     #[cfg(not(feature = "no_std"))]
+    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(not(target_arch = "wasm64"))]
     BasicTimePackage::init(lib);
     MoreStringPackage::init(lib);
 });

src/packages/time_basic.rs

@@ -1,3 +1,6 @@
+#![cfg(not(target_arch = "wasm32"))]
+#![cfg(not(target_arch = "wasm64"))]
+
 use super::logic::{eq, gt, gte, lt, lte, ne};
 use super::math_basic::MAX_INT;
 

tests/string.rs

@@ -159,6 +159,20 @@ fn test_string_substring() -> Result<(), Box<EvalAltResult>> {
 fn test_string_fn() -> Result<(), Box<EvalAltResult>> {
     let mut engine = Engine::new();
 
+    engine.register_fn("set_to_x", |ch: &mut char| *ch = 'X');
+
+    #[cfg(not(feature = "no_index"))]
+    #[cfg(not(feature = "no_object"))]
+    assert_eq!(
+        engine.eval::<String>(r#"let x="foo"; x[0].set_to_x(); x"#)?,
+        "Xoo"
+    );
+    #[cfg(not(feature = "no_index"))]
+    assert_eq!(
+        engine.eval::<String>(r#"let x="foo"; set_to_x(x[0]); x"#)?,
+        "foo"
+    );
+
     engine.register_fn("foo1", |s: &str| s.len() as INT);
     engine.register_fn("foo2", |s: ImmutableString| s.len() as INT);
     engine.register_fn("foo3", |s: String| s.len() as INT);