Merge branch 'master' into plugins

RELEASES.md

@@ -13,6 +13,7 @@ Breaking changes
 * Callback closure passed to `Engine::on_progress` now takes `&u64` instead of `u64` to be consistent with other callback signatures.
 * `Engine::register_indexer` is renamed to `Engine::register_indexer_get`.
 * `Module::set_indexer_fn` is renamed to `Module::set_indexer_get_fn`.
+* The tuple `ParseError` now exposes the internal fields and the `ParseError::error_type` and `ParseError::position` methods are removed.  The first tuple field is the `ParseErrorType` and the second tuple field is the `Position`.
 
 New features
 ------------

examples/repl.rs

@@ -7,28 +7,27 @@ use std::io::{stdin, stdout, Write};
 
 fn print_error(input: &str, err: EvalAltResult) {
     let lines: Vec<_> = input.trim().split('\n').collect();
+    let pos = err.position();
 
     let line_no = if lines.len() > 1 {
-        match err.position() {
+        if pos.is_none() {
-            p if p.is_none() => "".to_string(),
+            "".to_string()
-            p => format!("{}: ", p.line().unwrap()),
+        } else {
+            format!("{}: ", pos.line().unwrap())
         }
     } else {
         "".to_string()
     };
 
     // Print error
-    let pos = err.position();
     let pos_text = format!(" ({})", pos);
 
-    match pos {
+    if pos.is_none() {
-        p if p.is_none() => {
         // No position
         println!("{}", err);
-        }
+    } else {
-        p => {
         // Specific position
-            println!("{}{}", line_no, lines[p.line().unwrap() - 1]);
+        println!("{}{}", line_no, lines[pos.line().unwrap() - 1]);
 
         let err_text = match err {
             EvalAltResult::ErrorRuntime(err, _) if !err.is_empty() => {
@@ -40,11 +39,10 @@ fn print_error(input: &str, err: EvalAltResult) {
         println!(
             "{0:>1$} {2}",
             "^",
-                line_no.len() + p.position().unwrap(),
+            line_no.len() + pos.position().unwrap(),
             err_text.replace(&pos_text, "")
         );
     }
-    }
 }
 
 fn print_help() {

examples/rhai_runner.rs

@@ -1,4 +1,4 @@
-use rhai::{Engine, EvalAltResult};
+use rhai::{Engine, EvalAltResult, Position};
 
 #[cfg(not(feature = "no_optimize"))]
 use rhai::OptimizationLevel;
@@ -6,15 +6,17 @@ use rhai::OptimizationLevel;
 use std::{env, fs::File, io::Read, process::exit};
 
 fn eprint_error(input: &str, err: EvalAltResult) {
-    fn eprint_line(lines: &[&str], line: usize, pos: usize, err: &str) {
+    fn eprint_line(lines: &[&str], pos: Position, err: &str) {
+        let line = pos.line().unwrap();
+
         let line_no = format!("{}: ", line);
-        let pos_text = format!(" (line {}, position {})", line, pos);
+        let pos_text = format!(" ({})", pos);
 
         eprintln!("{}{}", line_no, lines[line - 1]);
         eprintln!(
             "{:>1$} {2}",
             "^",
-            line_no.len() + pos,
+            line_no.len() + pos.position().unwrap(),
             err.replace(&pos_text, "")
         );
         eprintln!("");
@@ -25,12 +27,10 @@ fn eprint_error(input: &str, err: EvalAltResult) {
     // Print error
     let pos = err.position();
 
-    match pos {
+    if pos.is_none() {
-        p if p.is_none() => {
         // No position
         eprintln!("{}", err);
-        }
+    } else {
-        p => {
         // Specific position
         let err_text = match err {
             EvalAltResult::ErrorRuntime(err, _) if !err.is_empty() => {
@@ -39,8 +39,7 @@ fn eprint_error(input: &str, err: EvalAltResult) {
             err => err.to_string(),
         };
 
-            eprint_line(&lines, p.line().unwrap(), p.position().unwrap(), &err_text)
+        eprint_line(&lines, pos, &err_text)
-        }
     }
 }
 

src/engine.rs

@@ -871,9 +871,7 @@ impl Engine {
 
         // If new functions are defined within the eval string, it is an error
         if ast.lib().num_fn() != 0 {
-            return Err(Box::new(EvalAltResult::ErrorParsing(
+            return Err(ParseErrorType::WrongFnDefinition.into());
-                ParseErrorType::WrongFnDefinition.into_err(Position::none()),
-            )));
         }
 
         let statements = mem::take(ast.statements_mut());

src/error.rs

@@ -1,5 +1,6 @@
 //! Module containing error definitions for the parsing process.
 
+use crate::result::EvalAltResult;
 use crate::token::Position;
 
 use crate::stdlib::{boxed::Box, char, error::Error, fmt, string::String};
@@ -123,113 +124,111 @@ impl ParseErrorType {
     pub(crate) fn into_err(self, pos: Position) -> ParseError {
         ParseError(Box::new(self), pos)
     }
+
+    pub(crate) fn desc(&self) -> &str {
+        match self {
+            Self::BadInput(p) => p,
+            Self::UnexpectedEOF => "Script is incomplete",
+            Self::UnknownOperator(_) => "Unknown operator",
+            Self::MissingToken(_, _) => "Expecting a certain token that is missing",
+            Self::MalformedCallExpr(_) => "Invalid expression in function call arguments",
+            Self::MalformedIndexExpr(_) => "Invalid index in indexing expression",
+            Self::MalformedInExpr(_) => "Invalid 'in' expression",
+            Self::DuplicatedProperty(_) => "Duplicated property in object map literal",
+            Self::ForbiddenConstantExpr(_) => "Expecting a constant",
+            Self::PropertyExpected => "Expecting name of a property",
+            Self::VariableExpected => "Expecting name of a variable",
+            Self::ExprExpected(_) => "Expecting an expression",
+            Self::FnMissingName => "Expecting name in function declaration",
+            Self::FnMissingParams(_) => "Expecting parameters in function declaration",
+            Self::FnDuplicatedParam(_,_) => "Duplicated parameters in function declaration",
+            Self::FnMissingBody(_) => "Expecting body statement block for function declaration",
+            Self::WrongFnDefinition => "Function definitions must be at global level and cannot be inside a block or another function",
+            Self::DuplicatedExport(_) => "Duplicated variable/function in export statement",
+            Self::WrongExport => "Export statement can only appear at global level",
+            Self::AssignmentToCopy => "Only a copy of the value is change with this assignment",
+            Self::AssignmentToConstant(_) => "Cannot assign to a constant value",
+            Self::ExprTooDeep => "Expression exceeds maximum complexity",
+            Self::LoopBreak => "Break statement should only be used inside a loop"
+        }
+    }
+}
+
+impl fmt::Display for ParseErrorType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::BadInput(s) | ParseErrorType::MalformedCallExpr(s) => {
+                write!(f, "{}", if s.is_empty() { self.desc() } else { s })
+            }
+            Self::ForbiddenConstantExpr(s) => {
+                write!(f, "Expecting a constant to assign to '{}'", s)
+            }
+            Self::UnknownOperator(s) => write!(f, "{}: '{}'", self.desc(), s),
+
+            Self::MalformedIndexExpr(s) => {
+                write!(f, "{}", if s.is_empty() { self.desc() } else { s })
+            }
+
+            Self::MalformedInExpr(s) => write!(f, "{}", if s.is_empty() { self.desc() } else { s }),
+
+            Self::DuplicatedProperty(s) => {
+                write!(f, "Duplicated property '{}' for object map literal", s)
+            }
+
+            Self::ExprExpected(s) => write!(f, "Expecting {} expression", s),
+
+            Self::FnMissingParams(s) => write!(f, "Expecting parameters for function '{}'", s),
+
+            Self::FnMissingBody(s) => {
+                write!(f, "Expecting body statement block for function '{}'", s)
+            }
+
+            Self::FnDuplicatedParam(s, arg) => {
+                write!(f, "Duplicated parameter '{}' for function '{}'", arg, s)
+            }
+
+            Self::DuplicatedExport(s) => write!(
+                f,
+                "Duplicated variable/function '{}' in export statement",
+                s
+            ),
+
+            Self::MissingToken(token, s) => write!(f, "Expecting '{}' {}", token, s),
+
+            Self::AssignmentToConstant(s) if s.is_empty() => write!(f, "{}", self.desc()),
+            Self::AssignmentToConstant(s) => write!(f, "Cannot assign to constant '{}'", s),
+            _ => write!(f, "{}", self.desc()),
+        }
+    }
 }
 
 /// Error when parsing a script.
 #[derive(Debug, Eq, PartialEq, Clone, Hash)]
-pub struct ParseError(pub(crate) Box<ParseErrorType>, pub(crate) Position);
+pub struct ParseError(pub Box<ParseErrorType>, pub Position);
-
-impl ParseError {
-    /// Get the parse error.
-    pub fn error_type(&self) -> &ParseErrorType {
-        &self.0
-    }
-
-    /// Get the location in the script of the error.
-    pub fn position(&self) -> Position {
-        self.1
-    }
-
-    pub(crate) fn desc(&self) -> &str {
-        match self.0.as_ref() {
-            ParseErrorType::BadInput(p) => p,
-            ParseErrorType::UnexpectedEOF => "Script is incomplete",
-            ParseErrorType::UnknownOperator(_) => "Unknown operator",
-            ParseErrorType::MissingToken(_, _) => "Expecting a certain token that is missing",
-            ParseErrorType::MalformedCallExpr(_) => "Invalid expression in function call arguments",
-            ParseErrorType::MalformedIndexExpr(_) => "Invalid index in indexing expression",
-            ParseErrorType::MalformedInExpr(_) => "Invalid 'in' expression",
-            ParseErrorType::DuplicatedProperty(_) => "Duplicated property in object map literal",
-            ParseErrorType::ForbiddenConstantExpr(_) => "Expecting a constant",
-            ParseErrorType::PropertyExpected => "Expecting name of a property",
-            ParseErrorType::VariableExpected => "Expecting name of a variable",
-            ParseErrorType::ExprExpected(_) => "Expecting an expression",
-            ParseErrorType::FnMissingName => "Expecting name in function declaration",
-            ParseErrorType::FnMissingParams(_) => "Expecting parameters in function declaration",
-            ParseErrorType::FnDuplicatedParam(_,_) => "Duplicated parameters in function declaration",
-            ParseErrorType::FnMissingBody(_) => "Expecting body statement block for function declaration",
-            ParseErrorType::WrongFnDefinition => "Function definitions must be at global level and cannot be inside a block or another function",
-            ParseErrorType::DuplicatedExport(_) => "Duplicated variable/function in export statement",
-            ParseErrorType::WrongExport => "Export statement can only appear at global level",
-            ParseErrorType::AssignmentToCopy => "Only a copy of the value is change with this assignment",
-            ParseErrorType::AssignmentToConstant(_) => "Cannot assign to a constant value",
-            ParseErrorType::ExprTooDeep => "Expression exceeds maximum complexity",
-            ParseErrorType::LoopBreak => "Break statement should only be used inside a loop"
-        }
-    }
-}
 
 impl Error for ParseError {}
 
 impl fmt::Display for ParseError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0.as_ref() {
+        fmt::Display::fmt(&self.0, f)?;
-            ParseErrorType::BadInput(s) | ParseErrorType::MalformedCallExpr(s) => {
-                write!(f, "{}", if s.is_empty() { self.desc() } else { s })?
-            }
-            ParseErrorType::ForbiddenConstantExpr(s) => {
-                write!(f, "Expecting a constant to assign to '{}'", s)?
-            }
-            ParseErrorType::UnknownOperator(s) => write!(f, "{}: '{}'", self.desc(), s)?,
 
-            ParseErrorType::MalformedIndexExpr(s) => {
-                write!(f, "{}", if s.is_empty() { self.desc() } else { s })?
-            }
-
-            ParseErrorType::MalformedInExpr(s) => {
-                write!(f, "{}", if s.is_empty() { self.desc() } else { s })?
-            }
-
-            ParseErrorType::DuplicatedProperty(s) => {
-                write!(f, "Duplicated property '{}' for object map literal", s)?
-            }
-
-            ParseErrorType::ExprExpected(s) => write!(f, "Expecting {} expression", s)?,
-
-            ParseErrorType::FnMissingParams(s) => {
-                write!(f, "Expecting parameters for function '{}'", s)?
-            }
-
-            ParseErrorType::FnMissingBody(s) => {
-                write!(f, "Expecting body statement block for function '{}'", s)?
-            }
-
-            ParseErrorType::FnDuplicatedParam(s, arg) => {
-                write!(f, "Duplicated parameter '{}' for function '{}'", arg, s)?
-            }
-
-            ParseErrorType::DuplicatedExport(s) => write!(
-                f,
-                "Duplicated variable/function '{}' in export statement",
-                s
-            )?,
-
-            ParseErrorType::MissingToken(token, s) => write!(f, "Expecting '{}' {}", token, s)?,
-
-            ParseErrorType::AssignmentToConstant(s) if s.is_empty() => {
-                write!(f, "{}", self.desc())?
-            }
-            ParseErrorType::AssignmentToConstant(s) => {
-                write!(f, "Cannot assign to constant '{}'", s)?
-            }
-            _ => write!(f, "{}", self.desc())?,
-        }
-
-        if !self.1.is_none() {
         // Do not write any position if None
-            Ok(())
+        if !self.1.is_none() {
-        } else {
+            write!(f, " ({})", self.1)?;
-            write!(f, " ({})", self.1)
         }
+
+        Ok(())
+    }
+}
+
+impl From<ParseErrorType> for Box<EvalAltResult> {
+    fn from(err: ParseErrorType) -> Self {
+        Box::new(EvalAltResult::ErrorParsing(err, Position::none()))
+    }
+}
+
+impl From<ParseError> for Box<EvalAltResult> {
+    fn from(err: ParseError) -> Self {
+        Box::new(EvalAltResult::ErrorParsing(*err.0, err.1))
     }
 }

src/parser.rs

@@ -16,7 +16,7 @@ use crate::stdlib::{
     char,
     collections::HashMap,
     format,
-    iter::{empty, Peekable},
+    iter::empty,
     mem,
     num::NonZeroUsize,
     ops::{Add, Deref, DerefMut},
@@ -751,15 +751,13 @@ fn parse_paren_expr(
         // ( xxx )
         (Token::RightParen, _) => Ok(expr),
         // ( <error>
-        (Token::LexError(err), pos) => {
+        (Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
-            return Err(PERR::BadInput(err.to_string()).into_err(settings.pos))
-        }
         // ( xxx ???
         (_, pos) => Err(PERR::MissingToken(
             Token::RightParen.into(),
             "for a matching ( in this expression".into(),
         )
-        .into_err(settings.pos)),
+        .into_err(pos)),
     }
 }
 
@@ -769,10 +767,9 @@ fn parse_call_expr(
     state: &mut ParseState,
     id: String,
     mut modules: Option<Box<ModuleRef>>,
-    mut settings: ParseSettings,
+    settings: ParseSettings,
 ) -> Result<Expr, ParseError> {
-    let (token, token_pos) = input.peek().unwrap();
+    let (token, _) = input.peek().unwrap();
-    settings.pos = *token_pos;
     settings.ensure_level_within_max_limit(state.max_expr_depth)?;
 
     let mut args = StaticVec::new();
@@ -888,7 +885,7 @@ fn parse_index_chain(
     input: &mut TokenStream,
     state: &mut ParseState,
     lhs: Expr,
-    settings: ParseSettings,
+    mut settings: ParseSettings,
 ) -> Result<Expr, ParseError> {
     settings.ensure_level_within_max_limit(state.max_expr_depth)?;
 
@@ -1031,11 +1028,12 @@ fn parse_index_chain(
             match input.peek().unwrap() {
                 // If another indexing level, right-bind it
                 (Token::LeftBracket, _) => {
-                    let idx_pos = eat_token(input, Token::LeftBracket);
+                    let prev_pos = settings.pos;
+                    settings.pos = eat_token(input, Token::LeftBracket);
                     // Recursively parse the indexing chain, right-binding each
                     let idx_expr = parse_index_chain(input, state, idx_expr, settings.level_up())?;
                     // Indexing binds to right
-                    Ok(Expr::Index(Box::new((lhs, idx_expr, settings.pos))))
+                    Ok(Expr::Index(Box::new((lhs, idx_expr, prev_pos))))
                 }
                 // Otherwise terminate the indexing chain
                 _ => {
@@ -1257,11 +1255,13 @@ fn parse_primary(
         }
 
         let (token, token_pos) = input.next().unwrap();
+        settings.pos = token_pos;
 
         root_expr = match (root_expr, token) {
             // Function call
             (Expr::Variable(x), Token::LeftParen) => {
                 let ((name, pos), modules, _, _) = *x;
+                settings.pos = pos;
                 parse_call_expr(input, state, name, modules, settings.level_up())?
             }
             (Expr::Property(_), _) => unreachable!(),
@@ -1269,6 +1269,7 @@ fn parse_primary(
             (Expr::Variable(x), Token::DoubleColon) => match input.next().unwrap() {
                 (Token::Identifier(id2), pos2) => {
                     let ((name, pos), mut modules, _, index) = *x;
+
                     if let Some(ref mut modules) = modules {
                         modules.push((name, pos));
                     } else {
@@ -1284,7 +1285,6 @@ fn parse_primary(
             // Indexing
             #[cfg(not(feature = "no_index"))]
             (expr, Token::LeftBracket) => {
-                settings.pos = token_pos;
                 parse_index_chain(input, state, expr, settings.level_up())?
             }
             // Unknown postfix operator
@@ -1416,9 +1416,11 @@ fn make_assignment_stmt<'a>(
     pos: Position,
 ) -> Result<Expr, ParseError> {
     match &lhs {
+        // var (non-indexed) = rhs
         Expr::Variable(x) if x.3.is_none() => {
             Ok(Expr::Assignment(Box::new((lhs, fn_name.into(), rhs, pos))))
         }
+        // var (indexed) = rhs
         Expr::Variable(x) => {
             let ((name, name_pos), _, _, index) = x.as_ref();
             match state.stack[(state.len() - index.unwrap().get())].1 {
@@ -1432,10 +1434,13 @@ fn make_assignment_stmt<'a>(
                 ScopeEntryType::Module => unreachable!(),
             }
         }
+        // xxx[???] = rhs, xxx.??? = rhs
         Expr::Index(x) | Expr::Dot(x) => match &x.0 {
+            // var[???] (non-indexed) = rhs, var.??? (non-indexed) = rhs
             Expr::Variable(x) if x.3.is_none() => {
                 Ok(Expr::Assignment(Box::new((lhs, fn_name.into(), rhs, pos))))
             }
+            // var[???] (indexed) = rhs, var.??? (indexed) = rhs
             Expr::Variable(x) => {
                 let ((name, name_pos), _, _, index) = x.as_ref();
                 match state.stack[(state.len() - index.unwrap().get())].1 {
@@ -1449,11 +1454,18 @@ fn make_assignment_stmt<'a>(
                     ScopeEntryType::Module => unreachable!(),
                 }
             }
+            // expr[???] = rhs, expr.??? = rhs
             _ => Err(PERR::AssignmentToCopy.into_err(x.0.position())),
         },
+        // const_expr = rhs
         expr if expr.is_constant() => {
             Err(PERR::AssignmentToConstant("".into()).into_err(lhs.position()))
         }
+        // ??? && ??? = rhs, ??? || ??? = rhs
+        Expr::And(_) | Expr::Or(_) => {
+            Err(PERR::BadInput("Possibly a typo of '=='?".to_string()).into_err(pos))
+        }
+        // expr = rhs
         _ => Err(PERR::AssignmentToCopy.into_err(lhs.position())),
     }
 }

src/result.rs

@@ -1,7 +1,7 @@
 //! Module containing error definitions for the evaluation process.
 
 use crate::any::Dynamic;
-use crate::error::ParseError;
+use crate::error::ParseErrorType;
 use crate::parser::INT;
 use crate::token::Position;
 
@@ -23,7 +23,7 @@ use crate::stdlib::path::PathBuf;
 #[derive(Debug)]
 pub enum EvalAltResult {
     /// Syntax error.
-    ErrorParsing(ParseError),
+    ErrorParsing(ParseErrorType, Position),
 
     /// Error reading from a script file. Wrapped value is the path of the script file.
     ///
@@ -101,7 +101,7 @@ impl EvalAltResult {
             #[cfg(not(feature = "no_std"))]
             Self::ErrorReadingScriptFile(_, _, _) => "Cannot read from script file",
 
-            Self::ErrorParsing(p) => p.desc(),
+            Self::ErrorParsing(p, _) => p.desc(),
             Self::ErrorInFunctionCall(_, _, _) => "Error in called function",
             Self::ErrorFunctionNotFound(_, _) => "Function not found",
             Self::ErrorBooleanArgMismatch(_, _) => "Boolean operator expects boolean operands",
@@ -153,95 +153,89 @@ impl Error for EvalAltResult {}
 impl fmt::Display for EvalAltResult {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let desc = self.desc();
+        let pos = self.position();
 
         match self {
             #[cfg(not(feature = "no_std"))]
-            Self::ErrorReadingScriptFile(path, pos, err) if pos.is_none() => {
+            Self::ErrorReadingScriptFile(path, _, err) => {
-                write!(f, "{} '{}': {}", desc, path.display(), err)
+                write!(f, "{} '{}': {}", desc, path.display(), err)?
-            }
-            #[cfg(not(feature = "no_std"))]
-            Self::ErrorReadingScriptFile(path, pos, err) => {
-                write!(f, "{} '{}': {} ({})", desc, path.display(), err, pos)
             }
 
-            Self::ErrorParsing(p) => write!(f, "Syntax error: {}", p),
+            Self::ErrorParsing(p, _) => write!(f, "Syntax error: {}", p)?,
 
-            Self::ErrorInFunctionCall(s, err, pos) => {
+            Self::ErrorInFunctionCall(s, err, _) => {
-                write!(f, "Error in call to function '{}' ({}): {}", s, pos, err)
+                write!(f, "Error in call to function '{}' : {}", s, err)?
             }
 
-            Self::ErrorFunctionNotFound(s, pos)
+            Self::ErrorFunctionNotFound(s, _)
-            | Self::ErrorVariableNotFound(s, pos)
+            | Self::ErrorVariableNotFound(s, _)
-            | Self::ErrorModuleNotFound(s, pos) => write!(f, "{}: '{}' ({})", desc, s, pos),
+            | Self::ErrorModuleNotFound(s, _) => write!(f, "{}: '{}'", desc, s)?,
 
-            Self::ErrorDotExpr(s, pos) if !s.is_empty() => write!(f, "{} {} ({})", desc, s, pos),
+            Self::ErrorDotExpr(s, _) if !s.is_empty() => write!(f, "{} {}", desc, s)?,
 
-            Self::ErrorIndexingType(_, pos)
+            Self::ErrorIndexingType(_, _)
-            | Self::ErrorNumericIndexExpr(pos)
+            | Self::ErrorNumericIndexExpr(_)
-            | Self::ErrorStringIndexExpr(pos)
+            | Self::ErrorStringIndexExpr(_)
-            | Self::ErrorImportExpr(pos)
+            | Self::ErrorImportExpr(_)
-            | Self::ErrorLogicGuard(pos)
+            | Self::ErrorLogicGuard(_)
-            | Self::ErrorFor(pos)
+            | Self::ErrorFor(_)
-            | Self::ErrorAssignmentToUnknownLHS(pos)
+            | Self::ErrorAssignmentToUnknownLHS(_)
-            | Self::ErrorInExpr(pos)
+            | Self::ErrorInExpr(_)
-            | Self::ErrorDotExpr(_, pos)
+            | Self::ErrorDotExpr(_, _)
-            | Self::ErrorTooManyOperations(pos)
+            | Self::ErrorTooManyOperations(_)
-            | Self::ErrorTooManyModules(pos)
+            | Self::ErrorTooManyModules(_)
-            | Self::ErrorStackOverflow(pos)
+            | Self::ErrorStackOverflow(_)
-            | Self::ErrorTerminated(pos) => write!(f, "{} ({})", desc, pos),
+            | Self::ErrorTerminated(_) => write!(f, "{}", desc)?,
 
-            Self::ErrorRuntime(s, pos) => {
+            Self::ErrorRuntime(s, _) => write!(f, "{}", if s.is_empty() { desc } else { s })?,
-                write!(f, "{} ({})", if s.is_empty() { desc } else { s }, pos)
+
+            Self::ErrorAssignmentToConstant(s, _) => write!(f, "{}: '{}'", desc, s)?,
+            Self::ErrorMismatchOutputType(s, _) => write!(f, "{}: {}", desc, s)?,
+            Self::ErrorArithmetic(s, _) => write!(f, "{}", s)?,
+
+            Self::ErrorLoopBreak(_, _) => write!(f, "{}", desc)?,
+            Self::Return(_, _) => write!(f, "{}", desc)?,
+
+            Self::ErrorBooleanArgMismatch(op, _) => {
+                write!(f, "{} operator expects boolean operands", op)?
             }
-
+            Self::ErrorCharMismatch(_) => write!(f, "string indexing expects a character value")?,
-            Self::ErrorAssignmentToConstant(s, pos) => write!(f, "{}: '{}' ({})", desc, s, pos),
+            Self::ErrorArrayBounds(_, index, _) if *index < 0 => {
-            Self::ErrorMismatchOutputType(s, pos) => write!(f, "{}: {} ({})", desc, s, pos),
+                write!(f, "{}: {} < 0", desc, index)?
-            Self::ErrorArithmetic(s, pos) => write!(f, "{} ({})", s, pos),
-
-            Self::ErrorLoopBreak(_, pos) => write!(f, "{} ({})", desc, pos),
-            Self::Return(_, pos) => write!(f, "{} ({})", desc, pos),
-
-            Self::ErrorBooleanArgMismatch(op, pos) => {
-                write!(f, "{} operator expects boolean operands ({})", op, pos)
             }
-            Self::ErrorCharMismatch(pos) => {
+            Self::ErrorArrayBounds(0, _, _) => write!(f, "{}", desc)?,
-                write!(f, "string indexing expects a character value ({})", pos)
+            Self::ErrorArrayBounds(1, index, _) => write!(
-            }
-            Self::ErrorArrayBounds(_, index, pos) if *index < 0 => {
-                write!(f, "{}: {} < 0 ({})", desc, index, pos)
-            }
-            Self::ErrorArrayBounds(0, _, pos) => write!(f, "{} ({})", desc, pos),
-            Self::ErrorArrayBounds(1, index, pos) => write!(
                 f,
-                "Array index {} is out of bounds: only one element in the array ({})",
+                "Array index {} is out of bounds: only one element in the array",
-                index, pos
+                index
-            ),
+            )?,
-            Self::ErrorArrayBounds(max, index, pos) => write!(
+            Self::ErrorArrayBounds(max, index, _) => write!(
                 f,
-                "Array index {} is out of bounds: only {} elements in the array ({})",
+                "Array index {} is out of bounds: only {} elements in the array",
-                index, max, pos
+                index, max
-            ),
+            )?,
-            Self::ErrorStringBounds(_, index, pos) if *index < 0 => {
+            Self::ErrorStringBounds(_, index, _) if *index < 0 => {
-                write!(f, "{}: {} < 0 ({})", desc, index, pos)
+                write!(f, "{}: {} < 0", desc, index)?
             }
-            Self::ErrorStringBounds(0, _, pos) => write!(f, "{} ({})", desc, pos),
+            Self::ErrorStringBounds(0, _, _) => write!(f, "{}", desc)?,
-            Self::ErrorStringBounds(1, index, pos) => write!(
+            Self::ErrorStringBounds(1, index, _) => write!(
                 f,
-                "String index {} is out of bounds: only one character in the string ({})",
+                "String index {} is out of bounds: only one character in the string",
-                index, pos
+                index
-            ),
+            )?,
-            Self::ErrorStringBounds(max, index, pos) => write!(
+            Self::ErrorStringBounds(max, index, _) => write!(
                 f,
-                "String index {} is out of bounds: only {} characters in the string ({})",
+                "String index {} is out of bounds: only {} characters in the string",
-                index, max, pos
+                index, max
-            ),
+            )?,
         }
-    }
-}
 
-impl From<ParseError> for Box<EvalAltResult> {
+        // Do not write any position if None
-    fn from(err: ParseError) -> Self {
+        if !pos.is_none() {
-        Box::new(EvalAltResult::ErrorParsing(err))
+            write!(f, " ({})", pos)?;
+        }
+
+        Ok(())
     }
 }
 
@@ -261,9 +255,8 @@ impl EvalAltResult {
             #[cfg(not(feature = "no_std"))]
             Self::ErrorReadingScriptFile(_, pos, _) => *pos,
 
-            Self::ErrorParsing(err) => err.position(),
+            Self::ErrorParsing(_, pos)
-
+            | Self::ErrorFunctionNotFound(_, pos)
-            Self::ErrorFunctionNotFound(_, pos)
             | Self::ErrorInFunctionCall(_, _, pos)
             | Self::ErrorBooleanArgMismatch(_, pos)
             | Self::ErrorCharMismatch(pos)
@@ -299,9 +292,8 @@ impl EvalAltResult {
             #[cfg(not(feature = "no_std"))]
             Self::ErrorReadingScriptFile(_, pos, _) => *pos = new_position,
 
-            Self::ErrorParsing(err) => err.1 = new_position,
+            Self::ErrorParsing(_, pos)
-
+            | Self::ErrorFunctionNotFound(_, pos)
-            Self::ErrorFunctionNotFound(_, pos)
             | Self::ErrorInFunctionCall(_, _, pos)
             | Self::ErrorBooleanArgMismatch(_, pos)
             | Self::ErrorCharMismatch(pos)

tests/call_fn.rs

@@ -1,19 +1,17 @@
 #![cfg(not(feature = "no_function"))]
-use rhai::{Engine, EvalAltResult, Func, ParseErrorType, Scope, INT};
+use rhai::{Engine, EvalAltResult, Func, ParseError, ParseErrorType, Scope, INT};
 
 #[test]
 fn test_fn() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
     // Expect duplicated parameters error
-    match engine
+    assert!(matches!(
+        engine
             .compile("fn hello(x, x) { x }")
-        .expect_err("should be error")
+            .expect_err("should be error"),
-        .error_type()
+        ParseError(x, _) if *x == ParseErrorType::FnDuplicatedParam("hello".to_string(), "x".to_string())
-    {
+    ));
-        ParseErrorType::FnDuplicatedParam(f, p) if f == "hello" && p == "x" => (),
-        _ => assert!(false, "wrong error"),
-    }
 
     Ok(())
 }

tests/constants.rs

@@ -7,14 +7,16 @@ fn test_constant() -> Result<(), Box<EvalAltResult>> {
     assert_eq!(engine.eval::<INT>("const x = 123; x")?, 123);
 
     assert!(matches!(
-        *engine.eval::<INT>("const x = 123; x = 42;").expect_err("expects error"),
+        *engine
-        EvalAltResult::ErrorParsing(err) if err.error_type() == &ParseErrorType::AssignmentToConstant("x".to_string())
+            .eval::<INT>("const x = 123; x = 42;")
+            .expect_err("expects error"),
+        EvalAltResult::ErrorParsing(ParseErrorType::AssignmentToConstant(x), _) if x == "x"
     ));
 
     #[cfg(not(feature = "no_index"))]
     assert!(matches!(
         *engine.eval::<INT>("const x = [1, 2, 3, 4, 5]; x[2] = 42;").expect_err("expects error"),
-        EvalAltResult::ErrorParsing(err) if err.error_type() == &ParseErrorType::AssignmentToConstant("x".to_string())
+        EvalAltResult::ErrorParsing(ParseErrorType::AssignmentToConstant(x), _) if x == "x"
     ));
 
     Ok(())

tests/expressions.rs

@@ -21,6 +21,8 @@ fn test_expressions() -> Result<(), Box<EvalAltResult>> {
     assert!(engine.eval_expression::<()>("x = 42").is_err());
     assert!(engine.compile_expression("let x = 42").is_err());
 
+    engine.compile("40 + { let x = 2; x }")?;
+
     Ok(())
 }
 

tests/looping.rs

@@ -1,4 +1,4 @@
-use rhai::{Engine, EvalAltResult, INT};
+use rhai::{Engine, EvalAltResult, ParseError, ParseErrorType, INT};
 
 #[test]
 fn test_loop() -> Result<(), Box<EvalAltResult>> {
@@ -26,5 +26,15 @@ fn test_loop() -> Result<(), Box<EvalAltResult>> {
         21
     );
 
+    assert!(matches!(
+        engine.compile("let x = 0; break;").expect_err("should error"),
+        ParseError(x, _) if *x == ParseErrorType::LoopBreak
+    ));
+
+    assert!(matches!(
+        engine.compile("let x = 0; if x > 0 { continue; }").expect_err("should error"),
+        ParseError(x, _) if *x == ParseErrorType::LoopBreak
+    ));
+
     Ok(())
 }

tests/modules.rs

@@ -1,5 +1,7 @@
 #![cfg(not(feature = "no_module"))]
-use rhai::{module_resolvers, Engine, EvalAltResult, Module, Scope, INT};
+use rhai::{
+    module_resolvers, Engine, EvalAltResult, Module, ParseError, ParseErrorType, Scope, INT,
+};
 
 #[test]
 fn test_module() {
@@ -231,3 +233,20 @@ fn test_module_from_ast() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_module_export() -> Result<(), Box<EvalAltResult>> {
+    let engine = Engine::new();
+
+    assert!(matches!(
+        engine.compile(r"let x = 10; { export x; }").expect_err("should error"),
+        ParseError(x, _) if *x == ParseErrorType::WrongExport
+    ));
+
+    assert!(matches!(
+        engine.compile(r"fn abc(x) { export x; }").expect_err("should error"),
+        ParseError(x, _) if *x == ParseErrorType::WrongExport
+    ));
+
+    Ok(())
+}