Add parse_json.

CHANGELOG.md

@@ -12,6 +12,11 @@ New features
 * It is now possible to specify a fixed _seed_ for use with the `ahash` hasher, via an environment variable, in order to force stable (i.e. deterministic) hashes for function signatures. This is necessary when using Rhai across shared-library boundaries.
 * A build script is now used to extract the environment variable (`RHAI_AHASH_SEED`) and splice it into the source code before compilation.
 
+Bug fixes
+---------
+
+* `Engine::parse_json` now returns an error on unquoted keys to be consistent with JSON specifications.
+
 Enhancements
 ------------
 
@@ -19,6 +24,7 @@ Enhancements
 * Due to a code refactor, built-in operators for standard types now run even faster, in certain cases by 20-30%.
 * `Scope` is now serializable and deserializable via `serde`.
 * `Scope` now contains a const generic parameter that allows specifying how many entries to be kept inline.
+* `parse_json` function is added to parse a JSON string into an object map.
 
 
 Version 1.10.1

src/api/compile.rs

@@ -295,6 +295,6 @@ impl Engine {
 
         let mut peekable = stream.peekable();
         let mut state = ParseState::new(self, scope, Default::default(), tokenizer_control);
-        self.parse_global_expr(&mut peekable, &mut state, self.optimization_level)
+        self.parse_global_expr(&mut peekable, &mut state, |_| {}, self.optimization_level)
     }
 }

src/api/eval.rs

@@ -122,6 +122,7 @@ impl Engine {
         let ast = self.parse_global_expr(
             &mut stream.peekable(),
             &mut state,
+            |_| {},
             #[cfg(not(feature = "no_optimize"))]
             OptimizationLevel::None,
             #[cfg(feature = "no_optimize")]

src/api/json.rs

@@ -23,7 +23,7 @@ impl Engine {
     /// JSON sub-objects are handled transparently.
     ///
     /// This function can be used together with [`format_map_as_json`] to work with JSON texts
-    /// without using the [`serde`](https://crates.io/crates/serde) crate (which is heavy).
+    /// without using the [`serde_json`](https://crates.io/crates/serde_json) crate (which is heavy).
     ///
     /// # Example
     ///
@@ -122,6 +122,7 @@ impl Engine {
         let ast = self.parse_global_expr(
             &mut stream.peekable(),
             &mut state,
+            |s| s.allow_unquoted_map_properties = false,
             #[cfg(not(feature = "no_optimize"))]
             OptimizationLevel::None,
             #[cfg(feature = "no_optimize")]
@@ -137,7 +138,7 @@ impl Engine {
 /// Not available under `no_std`.
 ///
 /// This function can be used together with [`Engine::parse_json`] to work with JSON texts
-/// without using the [`serde`](https://crates.io/crates/serde) crate (which is heavy).
+/// without using the [`serde_json`](https://crates.io/crates/serde_json) crate (which is heavy).
 ///
 /// # Data types
 ///

src/packages/lang_core.rs

@@ -88,7 +88,6 @@ mod core_functions {
         #[cfg(feature = "f32_float")]
         std::thread::sleep(std::time::Duration::from_secs_f32(seconds));
     }
-
     /// Block the current thread for a particular number of `seconds`.
     #[cfg(not(feature = "no_std"))]
     pub fn sleep(seconds: INT) {
@@ -97,6 +96,23 @@ mod core_functions {
         }
         std::thread::sleep(std::time::Duration::from_secs(seconds as u64));
     }
+
+    /// Parse a JSON string into a value.
+    ///
+    /// # Example
+    ///
+    /// ```rhai
+    /// let m = parse_json(`{"a":1, "b":2, "c":3}`);
+    ///
+    /// print(m);       // prints #{"a":1, "b":2, "c":3}
+    /// ```
+    #[cfg(not(feature = "no_index"))]
+    #[cfg(not(feature = "no_object"))]
+    #[cfg(feature = "metadata")]
+    #[rhai_fn(return_raw)]
+    pub fn parse_json(_ctx: NativeCallContext, json: &str) -> RhaiResultOf<Dynamic> {
+        serde_json::from_str(json).map_err(|err| err.to_string().into())
+    }
 }
 
 #[cfg(not(feature = "no_function"))]

src/packages/map_basic.rs

@@ -2,7 +2,7 @@
 
 use crate::engine::OP_EQUALS;
 use crate::plugin::*;
-use crate::{def_package, format_map_as_json, Dynamic, ImmutableString, Map, RhaiResultOf, INT};
+use crate::{def_package, Dynamic, ImmutableString, Map, NativeCallContext, RhaiResultOf, INT};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -304,6 +304,9 @@ mod map_functions {
     /// print(m.to_json());     // prints {"a":1, "b":2, "c":3}
     /// ```
     pub fn to_json(map: &mut Map) -> String {
-        format_map_as_json(map)
+        #[cfg(feature = "metadata")]
+        return serde_json::to_string(map).unwrap_or_else(|_| "ERROR".into());
+        #[cfg(not(feature = "metadata"))]
+        return crate::format_map_as_json(map);
     }
 }

src/parser.rs

@@ -287,26 +287,28 @@ impl<'e> ParseState<'e> {
 
 /// A type that encapsulates all the settings for a particular parsing function.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-struct ParseSettings {
+pub(crate) struct ParseSettings {
     /// Is the construct being parsed located at global level?
-    at_global_level: bool,
+    pub at_global_level: bool,
     /// Is the construct being parsed located inside a function definition?
     #[cfg(not(feature = "no_function"))]
-    in_fn_scope: bool,
+    pub in_fn_scope: bool,
     /// Is the construct being parsed located inside a closure definition?
     #[cfg(not(feature = "no_function"))]
     #[cfg(not(feature = "no_closure"))]
-    in_closure: bool,
+    pub in_closure: bool,
     /// Is the construct being parsed located inside a breakable loop?
-    is_breakable: bool,
+    pub is_breakable: bool,
     /// Allow statements in blocks?
-    allow_statements: bool,
+    pub allow_statements: bool,
+    /// Allow unquoted map properties?
+    pub allow_unquoted_map_properties: bool,
     /// Language options in effect (overrides Engine options).
-    options: LangOptions,
+    pub options: LangOptions,
     /// Current expression nesting level.
-    level: usize,
+    pub level: usize,
     /// Current position.
-    pos: Position,
+    pub pos: Position,
 }
 
 impl ParseSettings {
@@ -996,6 +998,9 @@ impl Engine {
             }
 
             let (name, pos) = match input.next().expect(NEVER_ENDS) {
+                (Token::Identifier(..), pos) if !settings.allow_unquoted_map_properties => {
+                    return Err(PERR::PropertyExpected.into_err(pos))
+                }
                 (Token::Identifier(s) | Token::StringConstant(s), pos) => {
                     if map.iter().any(|(p, ..)| **p == *s) {
                         return Err(PERR::DuplicatedProperty(s.to_string()).into_err(pos));
@@ -3326,6 +3331,7 @@ impl Engine {
                             in_closure: false,
                             is_breakable: false,
                             allow_statements: true,
+                            allow_unquoted_map_properties: settings.allow_unquoted_map_properties,
                             level: 0,
                             options,
                             pos,
@@ -3793,6 +3799,7 @@ impl Engine {
         &self,
         input: &mut TokenStream,
         state: &mut ParseState,
+        process_settings: impl Fn(&mut ParseSettings),
         _optimization_level: OptimizationLevel,
     ) -> ParseResult<AST> {
         let mut functions = StraightHashMap::default();
@@ -3802,7 +3809,7 @@ impl Engine {
         #[cfg(not(feature = "no_function"))]
         options.remove(LangOptions::ANON_FN);
 
-        let settings = ParseSettings {
+        let mut settings = ParseSettings {
             at_global_level: true,
             #[cfg(not(feature = "no_function"))]
             in_fn_scope: false,
@@ -3811,10 +3818,13 @@ impl Engine {
             in_closure: false,
             is_breakable: false,
             allow_statements: false,
+            allow_unquoted_map_properties: true,
             level: 0,
             options,
-            pos: Position::NONE,
+            pos: Position::START,
         };
+        process_settings(&mut settings);
+
         let expr = self.parse_expr(input, state, &mut functions, settings)?;
 
         assert!(functions.is_empty());
@@ -3853,12 +3863,11 @@ impl Engine {
         &self,
         input: &mut TokenStream,
         state: &mut ParseState,
+        process_settings: impl Fn(&mut ParseSettings),
     ) -> ParseResult<(StmtBlockContainer, StaticVec<Shared<ScriptFnDef>>)> {
         let mut statements = StmtBlockContainer::new_const();
         let mut functions = StraightHashMap::default();
-
-        while !input.peek().expect(NEVER_ENDS).0.is_eof() {
-            let settings = ParseSettings {
+        let mut settings = ParseSettings {
             at_global_level: true,
             #[cfg(not(feature = "no_function"))]
             in_fn_scope: false,
@@ -3867,11 +3876,14 @@ impl Engine {
             in_closure: false,
             is_breakable: false,
             allow_statements: true,
+            allow_unquoted_map_properties: true,
             options: self.options,
             level: 0,
-                pos: Position::NONE,
+            pos: Position::START,
         };
+        process_settings(&mut settings);
 
+        while !input.peek().expect(NEVER_ENDS).0.is_eof() {
             let stmt = self.parse_stmt(input, state, &mut functions, settings)?;
 
             if stmt.is_noop() {
@@ -3918,7 +3930,7 @@ impl Engine {
         state: &mut ParseState,
         _optimization_level: OptimizationLevel,
     ) -> ParseResult<AST> {
-        let (statements, _lib) = self.parse_global_level(input, state)?;
+        let (statements, _lib) = self.parse_global_level(input, state, |_| {})?;
 
         #[cfg(not(feature = "no_optimize"))]
         return Ok(crate::optimizer::optimize_into_ast(

src/types/error.rs

@@ -251,9 +251,9 @@ impl<T: AsRef<str>> From<T> for EvalAltResult {
 
 impl<T: AsRef<str>> From<T> for Box<EvalAltResult> {
     #[cold]
-    #[inline(never)]
+    #[inline(always)]
     fn from(err: T) -> Self {
-        EvalAltResult::ErrorRuntime(err.as_ref().to_string().into(), Position::NONE).into()
+        Into::<EvalAltResult>::into(err).into()
     }
 }
 

tests/maps.rs

@@ -276,6 +276,11 @@ fn test_map_json() -> Result<(), Box<EvalAltResult>> {
         EvalAltResult::ErrorMismatchOutputType(..)
     ));
 
+    assert!(matches!(
+        *engine.parse_json("{a:42}", true).expect_err("should error"),
+        EvalAltResult::ErrorParsing(..)
+    ));
+
     assert!(matches!(
         *engine
             .parse_json("#{a:123}", true)