Improve error messages to lists.

Cargo.toml

@@ -13,6 +13,7 @@ include = [
     "scripts/*.rhai",
     "Cargo.toml"
 ]
+keywords = [ "scripting" ]
 
 [dependencies]
 num-traits = "0.2.11"

README.md

@@ -171,7 +171,7 @@ let ast = engine.compile("40 + 2")?;
 for _ in 0..42 {
     let result: i64 = engine.eval_ast(&ast)?;
 
-    println!("Answer: {}", result);  // prints 42
+    println!("Answer #{}: {}", i, result);  // prints 42
 }
 ```
 
@@ -193,14 +193,17 @@ use rhai::Engine;
 let mut engine = Engine::new();
 
 // Define a function in a script and load it into the Engine.
-engine.consume(true,        // pass true to 'retain_functions' otherwise these functions
+// Pass true to 'retain_functions' otherwise these functions will be cleared at the end of consume()
-    r"                      //   will be cleared at the end of consume()
+engine.consume(true,
-        fn hello(x, y) {    // a function with two parameters: String and i64
+    r"
-            x.len() + y     //   returning i64
+        // a function with two parameters: String and i64
+        fn hello(x, y) {
+            x.len() + y
         }
 
-        fn hello(x) {       // functions can be overloaded: this one takes only one parameter
+        // functions can be overloaded: this one takes only one parameter
-            x * 2           //   returning i64
+        fn hello(x) {
+            x * 2
         }
     ")?;
 
@@ -495,22 +498,21 @@ let result = engine.eval::<i64>("let x = new_ts(); x.foo()")?;
 println!("result: {}", result); // prints 1
 ```
 
-`type_of` works fine with custom types and returns the name of the type:
+`type_of` works fine with custom types and returns the name of the type. If `register_type_with_name` is used to register the custom type
+with a special "pretty-print" name, `type_of` will return that name instead.
 
 ```rust
 let x = new_ts();
 print(x.type_of());     // prints "foo::bar::TestStruct"
+                        // prints "Hello" if TestStruct is registered with
+                        //   engine.register_type_with_name::<TestStruct>("Hello")?;
 ```
 
-If `register_type_with_name` is used to register the custom type with a special "pretty-print" name, `type_of` will return that name instead.
-
 Getters and setters
 -------------------
 
 Similarly, custom types can expose members by registering a `get` and/or `set` function.
 
-For example:
-
 ```rust
 #[derive(Clone)]
 struct TestStruct {
@@ -565,8 +567,8 @@ fn main() -> Result<(), EvalAltResult>
     // Then push some initialized variables into the state
     // NOTE: Remember the system number types in Rhai are i64 (i32 if 'only_i32') ond f64.
     //       Better stick to them or it gets hard working with the script.
-    scope.push("y".into(), 42_i64);
+    scope.push("y", 42_i64);
-    scope.push("z".into(), 999_i64);
+    scope.push("z", 999_i64);
 
     // First invocation
     engine.eval_with_scope::<()>(&mut scope, r"
@@ -684,7 +686,7 @@ Numeric operators generally follow C styles.
 | `%`      | Modulo (remainder)                                          |               |
 | `~`      | Power                                                       |               |
 | `&`      | Binary _And_ bit-mask                                       |      Yes      |
-| `|`      | Binary _Or_ bit-mask                                        |      Yes      |
+| `\|`     | Binary _Or_ bit-mask                                        |      Yes      |
 | `^`      | Binary _Xor_ bit-mask                                       |      Yes      |
 | `<<`     | Left bit-shift                                              |      Yes      |
 | `>>`     | Right bit-shift                                             |      Yes      |
@@ -948,9 +950,9 @@ Boolean operators
 | -------- | ------------------------------- |
 | `!`      | Boolean _Not_                   |
 | `&&`     | Boolean _And_ (short-circuits)  |
-| `||`     | Boolean _Or_ (short-circuits)   |
+| `\|\|`   | Boolean _Or_ (short-circuits)   |
 | `&`      | Boolean _And_ (full evaluation) |
-| `|`      | Boolean _Or_ (full evaluation)  |
+| `\|`     | Boolean _Or_ (full evaluation)  |
 
 Double boolean operators `&&` and `||` _short-circuit_, meaning that the second operand will not be evaluated
 if the first one already proves the condition wrong.

src/engine.rs

@@ -1031,30 +1031,29 @@ impl Engine<'_> {
             // Block scope
             Stmt::Block(block, _) => {
                 let prev_len = scope.len();
-                let mut last_result: Result<Dynamic, EvalAltResult> = Ok(().into_dynamic());
+                let mut result: Result<Dynamic, EvalAltResult> = Ok(().into_dynamic());
 
-                for block_stmt in block.iter() {
+                for stmt in block.iter() {
-                    last_result = self.eval_stmt(scope, block_stmt);
+                    result = self.eval_stmt(scope, stmt);
 
-                    if let Err(x) = last_result {
+                    if result.is_err() {
-                        last_result = Err(x);
                         break;
                     }
                 }
 
                 scope.rewind(prev_len);
 
-                last_result
+                result
             }
 
             // If-else statement
-            Stmt::IfElse(guard, body, else_body) => self
+            Stmt::IfElse(guard, if_body, else_body) => self
                 .eval_expr(scope, guard)?
                 .downcast::<bool>()
                 .map_err(|_| EvalAltResult::ErrorIfGuard(guard.position()))
                 .and_then(|guard_val| {
                     if *guard_val {
-                        self.eval_stmt(scope, body)
+                        self.eval_stmt(scope, if_body)
                     } else if let Some(stmt) = else_body {
                         self.eval_stmt(scope, stmt.as_ref())
                     } else {

src/error.rs

@@ -58,6 +58,8 @@ pub enum ParseErrorType {
     /// An open `[` is missing the corresponding closing `]`.
     #[cfg(not(feature = "no_index"))]
     MissingRightBracket(String),
+    /// A list of expressions is missing the separating ','.
+    MissingComma(String),
     /// An expression in function call arguments `()` has syntax error.
     MalformedCallExpr(String),
     /// An expression in indexing brackets `[]` has syntax error.
@@ -116,6 +118,7 @@ impl ParseError {
             ParseErrorType::MissingRightBrace(_) => "Expecting '}'",
             #[cfg(not(feature = "no_index"))]
             ParseErrorType::MissingRightBracket(_) => "Expecting ']'",
+            ParseErrorType::MissingComma(_) => "Expecting ','",
             ParseErrorType::MalformedCallExpr(_) => "Invalid expression in function call arguments",
             #[cfg(not(feature = "no_index"))]
             ParseErrorType::MalformedIndexExpr(_) => "Invalid index in indexing expression",
@@ -165,6 +168,8 @@ impl fmt::Display for ParseError {
             #[cfg(not(feature = "no_index"))]
             ParseErrorType::MissingRightBracket(ref s) => write!(f, "{} for {}", self.desc(), s)?,
 
+            ParseErrorType::MissingComma(ref s) => write!(f, "{} for {}", self.desc(), s)?,
+
             ParseErrorType::AssignmentToConstant(ref s) if s.is_empty() => {
                 write!(f, "{}", self.desc())?
             }