Merge pull request #224 from schungx/master

Bug fix - Allow module access in closures.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rhai"
-version = "0.19.0"
+version = "0.18.3"
 edition = "2018"
 authors = ["Jonathan Turner", "Lukáš Hozda", "Stephen Chung"]
 description = "Embedded scripting for Rust"

RELEASES.md

@@ -1,7 +1,17 @@
 Rhai Release Notes
 ==================
 
-Version 0.19.0
+Version 0.18.3
+==============
+
+Bug fixes
+---------
+
+* `Engine::compile_expression`, `Engine::eval_expression` etc. no longer parse anonymous functions and closures.
+* Imported modules now work inside closures.
+
+
+Version 0.18.2
 ==============
 
 Bug fixes

doc/src/engine/expressions.md

@@ -11,9 +11,11 @@ In these cases, use the `Engine::compile_expression` and `Engine::eval_expressio
 let result = engine.eval_expression::<i64>("2 + (10 + 10) * 2")?;
 ```
 
-When evaluating _expressions_, no full-blown statement (e.g. `if`, `while`, `for`) - not even variable assignment -
+When evaluating _expressions_, no full-blown statement (e.g. `if`, `while`, `for`, `fn`) - not even variable assignment -
 is supported and will be considered parse errors when encountered.
 
+[Closures] and [anonymous functions] are also not supported because in the background they compile to functions.
+
 ```rust
 // The following are all syntax errors because the script is not an expression.
 

src/api.rs

@@ -2,7 +2,7 @@
 
 use crate::any::{Dynamic, Variant};
 use crate::engine::{Engine, Imports, State};
-use crate::error::{ParseError, ParseErrorType};
+use crate::error::ParseError;
 use crate::fn_native::{IteratorFn, SendSync};
 use crate::module::{FuncReturn, Module};
 use crate::optimize::OptimizationLevel;
@@ -18,6 +18,7 @@ use crate::engine::{FN_IDX_GET, FN_IDX_SET};
 #[cfg(not(feature = "no_object"))]
 use crate::{
     engine::{make_getter, make_setter, Map},
+    error::ParseErrorType,
     fn_register::{RegisterFn, RegisterResultFn},
     token::Token,
 };
@@ -34,7 +35,6 @@ use crate::optimize::optimize_into_ast;
 use crate::stdlib::{
     any::{type_name, TypeId},
     boxed::Box,
-    string::ToString,
 };
 
 #[cfg(not(feature = "no_optimize"))]
@@ -944,8 +944,8 @@ impl Engine {
             ["#", json_text]
         } else {
             return Err(ParseErrorType::MissingToken(
-                Token::LeftBrace.syntax().to_string(),
-                "to start a JSON object hash".to_string(),
+                Token::LeftBrace.syntax().into(),
+                "to start a JSON object hash".into(),
             )
             .into_err(Position::new(1, (json.len() - json_text.len() + 1) as u16))
             .into());

src/parser.rs

@@ -1645,11 +1645,22 @@ fn parse_primary(
             }
             Expr::Variable(Box::new(((s, settings.pos), None, 0, None)))
         }
+        // Module qualification
+        #[cfg(not(feature = "no_module"))]
+        Token::Identifier(s) if *next_token == Token::DoubleColon => {
+            // Once the identifier consumed we must enable next variables capturing
+            #[cfg(not(feature = "no_closure"))]
+            {
+                state.allow_capture = true;
+            }
+            Expr::Variable(Box::new(((s, settings.pos), None, 0, None)))
+        }
         // Normal variable access
         Token::Identifier(s) => {
             let index = state.access_var(&s, settings.pos);
             Expr::Variable(Box::new(((s, settings.pos), None, 0, index)))
         }
+
         // Function call is allowed to have reserved keyword
         Token::Reserved(s) if *next_token == Token::LeftParen || *next_token == Token::Bang => {
             if is_keyword_function(&s) {
@@ -1658,6 +1669,7 @@ fn parse_primary(
                 return Err(PERR::Reserved(s).into_err(settings.pos));
             }
         }
+
         // Access to `this` as a variable is OK
         Token::Reserved(s) if s == KEYWORD_THIS && *next_token != Token::LeftParen => {
             if !settings.is_function_scope {
@@ -1669,9 +1681,11 @@ fn parse_primary(
                 Expr::Variable(Box::new(((s, settings.pos), None, 0, None)))
             }
         }
+
         Token::Reserved(s) if is_valid_identifier(s.chars()) => {
             return Err(PERR::Reserved(s).into_err(settings.pos));
         }
+
         Token::LeftParen => parse_paren_expr(input, state, lib, settings.level_up())?,
         #[cfg(not(feature = "no_index"))]
         Token::LeftBracket => parse_array_literal(input, state, lib, settings.level_up())?,
@@ -1680,6 +1694,7 @@ fn parse_primary(
         Token::True => Expr::True(settings.pos),
         Token::False => Expr::False(settings.pos),
         Token::LexError(err) => return Err(err.into_err(settings.pos)),
+
         _ => {
             return Err(
                 PERR::BadInput(format!("Unexpected '{}'", token.syntax())).into_err(settings.pos)
@@ -1862,7 +1877,7 @@ fn parse_unary(
         }
         // | ...
         #[cfg(not(feature = "no_function"))]
-        Token::Pipe | Token::Or => {
+        Token::Pipe | Token::Or if settings.allow_anonymous_fn => {
             let mut new_state = ParseState::new(
                 state.engine,
                 #[cfg(not(feature = "unchecked"))]
@@ -3353,6 +3368,8 @@ impl Engine {
         };
         let expr = parse_expr(input, &mut state, &mut functions, settings)?;
 
+        assert!(functions.is_empty());
+
         match input.peek().unwrap() {
             (Token::EOF, _) => (),
             // Return error if the expression doesn't end

tests/call_fn.rs

@@ -120,6 +120,20 @@ fn test_fn_ptr_raw() -> Result<(), Box<EvalAltResult>> {
         42
     );
 
+    assert_eq!(
+        engine.eval::<INT>(
+            r#"
+                fn foo(x, y) { this += x + y; }
+
+                let x = 40;
+                let v = 1;
+                x.bar(Fn("foo").curry(v), 1);
+                x
+            "#
+        )?,
+        42
+    );
+
     assert!(matches!(
         *engine.eval::<INT>(
             r#"

tests/closures.rs

@@ -1,7 +1,12 @@
 #![cfg(not(feature = "no_function"))]
-use rhai::{Dynamic, Engine, EvalAltResult, FnPtr, Module, RegisterFn, INT};
+use rhai::{Dynamic, Engine, EvalAltResult, FnPtr, Module, ParseErrorType, RegisterFn, Scope, INT};
 use std::any::TypeId;
+use std::cell::RefCell;
 use std::mem::take;
+use std::rc::Rc;
+
+#[cfg(not(feature = "no_object"))]
+use rhai::Map;
 
 #[test]
 fn test_fn_ptr_curry_call() -> Result<(), Box<EvalAltResult>> {
@@ -39,6 +44,14 @@ fn test_fn_ptr_curry_call() -> Result<(), Box<EvalAltResult>> {
 fn test_closures() -> Result<(), Box<EvalAltResult>> {
     let mut engine = Engine::new();
 
+    assert!(matches!(
+        *engine
+            .compile_expression("let f = |x| {};")
+            .expect_err("should error")
+            .0,
+        ParseErrorType::BadInput(_)
+    ));
+
     assert_eq!(
         engine.eval::<INT>(
             r#"
@@ -181,3 +194,59 @@ fn test_closures_data_race() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+type MyType = Rc<RefCell<INT>>;
+
+#[test]
+#[cfg(not(feature = "no_object"))]
+#[cfg(not(feature = "sync"))]
+fn test_closure_shared_obj() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    // Register API on MyType
+    engine
+        .register_type_with_name::<MyType>("MyType")
+        .register_get_set(
+            "data",
+            |p: &mut MyType| *p.borrow(),
+            |p: &mut MyType, value: INT| *p.borrow_mut() = value,
+        )
+        .register_fn("+=", |p1: &mut MyType, p2: MyType| {
+            *p1.borrow_mut() += *p2.borrow()
+        })
+        .register_fn("-=", |p1: &mut MyType, p2: MyType| {
+            *p1.borrow_mut() -= *p2.borrow()
+        });
+
+    let engine = engine; // Make engine immutable
+
+    let code = r#"
+        #{
+            name: "A",
+            description: "B",
+            cost: 1,
+            health_added: 0,
+            action: |p1, p2| { p1 += p2 }
+        }
+    "#;
+
+    let ast = engine.compile(code)?;
+    let res = engine.eval_ast::<Map>(&ast)?;
+
+    // Make closure
+    let f = move |p1: MyType, p2: MyType| -> Result<(), Box<EvalAltResult>> {
+        let action_ptr = res["action"].clone().cast::<FnPtr>();
+        let name = action_ptr.fn_name();
+        engine.call_fn::<_, ()>(&mut Scope::new(), &ast, name, (p1, p2))
+    };
+
+    // Test closure
+    let p1 = Rc::new(RefCell::new(41));
+    let p2 = Rc::new(RefCell::new(1));
+
+    f(p1.clone(), p2.clone())?;
+
+    assert_eq!(*p1.borrow(), 42);
+
+    Ok(())
+}