rhai/src/result.rs

267 lines
12 KiB
Rust

//! Module containing error definitions for the evaluation process.
use crate::any::Dynamic;
use crate::error::ParseError;
use crate::parser::{Position, INT};
use crate::stdlib::{
error::Error,
fmt,
string::{String, ToString},
};
#[cfg(not(feature = "no_std"))]
use crate::stdlib::path::PathBuf;
/// Evaluation result.
///
/// All wrapped `Position` values represent the location in the script where the error occurs.
#[derive(Debug)]
pub enum EvalAltResult {
/// Syntax error.
ErrorParsing(ParseError),
/// Call to an unknown function. Wrapped value is the name of the function.
ErrorFunctionNotFound(String, Position),
/// Function call has incorrect number of arguments.
/// Wrapped values are the name of the function, the number of parameters required
/// and the actual number of arguments passed.
ErrorFunctionArgsMismatch(String, usize, usize, Position),
/// Non-boolean operand encountered for boolean operator. Wrapped value is the operator.
ErrorBooleanArgMismatch(String, Position),
/// Non-character value encountered where a character is required.
ErrorCharMismatch(Position),
/// Array access out-of-bounds.
/// Wrapped values are the current number of elements in the array and the index number.
ErrorArrayBounds(usize, INT, Position),
/// String indexing out-of-bounds.
/// Wrapped values are the current number of characters in the string and the index number.
ErrorStringBounds(usize, INT, Position),
/// Trying to index into a type that is not an array and not a string.
ErrorIndexingType(String, Position),
/// Trying to index into an array or string with an index that is not `i64`.
ErrorIndexExpr(Position),
/// The guard expression in an `if` or `while` statement does not return a boolean value.
ErrorLogicGuard(Position),
/// The `for` statement encounters a type that is not an iterator.
ErrorFor(Position),
/// Usage of an unknown variable. Wrapped value is the name of the variable.
ErrorVariableNotFound(String, Position),
/// Assignment to an inappropriate LHS (left-hand-side) expression.
ErrorAssignmentToUnknownLHS(Position),
/// Assignment to a constant variable.
ErrorAssignmentToConstant(String, Position),
/// Returned type is not the same as the required output type.
/// Wrapped value is the type of the actual result.
ErrorMismatchOutputType(String, Position),
/// Error reading from a script file. Wrapped value is the path of the script file.
#[cfg(not(feature = "no_std"))]
ErrorReadingScriptFile(PathBuf, std::io::Error),
/// Inappropriate member access.
ErrorDotExpr(String, Position),
/// Arithmetic error encountered. Wrapped value is the error message.
ErrorArithmetic(String, Position),
/// Run-time error encountered. Wrapped value is the error message.
ErrorRuntime(String, Position),
/// Breaking out of loops - not an error if within a loop.
ErrorLoopBreak(Position),
/// Not an error: Value returned from a script via the `return` keyword.
/// Wrapped value is the result value.
Return(Dynamic, Position),
}
impl EvalAltResult {
pub(crate) fn desc(&self) -> &str {
match self {
Self::ErrorParsing(p) => p.desc(),
Self::ErrorFunctionNotFound(_, _) => "Function not found",
Self::ErrorFunctionArgsMismatch(_, _, _, _) => {
"Function call with wrong number of arguments"
}
Self::ErrorBooleanArgMismatch(_, _) => "Boolean operator expects boolean operands",
Self::ErrorCharMismatch(_) => "Character expected",
Self::ErrorIndexExpr(_) => "Indexing into an array or string expects an integer index",
Self::ErrorIndexingType(_, _) => {
"Indexing can only be performed on an array or a string"
}
Self::ErrorArrayBounds(_, index, _) if *index < 0 => {
"Array access expects non-negative index"
}
Self::ErrorArrayBounds(0, _, _) => "Access of empty array",
Self::ErrorArrayBounds(_, _, _) => "Array index out of bounds",
Self::ErrorStringBounds(_, index, _) if *index < 0 => {
"Indexing a string expects a non-negative index"
}
Self::ErrorStringBounds(0, _, _) => "Indexing of empty string",
Self::ErrorStringBounds(_, _, _) => "String index out of bounds",
Self::ErrorLogicGuard(_) => "Boolean expression expected",
Self::ErrorFor(_) => "For loop expects array or range",
Self::ErrorVariableNotFound(_, _) => "Variable not found",
Self::ErrorAssignmentToUnknownLHS(_) => {
"Assignment to an unsupported left-hand side expression"
}
Self::ErrorAssignmentToConstant(_, _) => "Assignment to a constant variable",
Self::ErrorMismatchOutputType(_, _) => "Output type is incorrect",
#[cfg(not(feature = "no_std"))]
Self::ErrorReadingScriptFile(_, _) => "Cannot read from script file",
Self::ErrorDotExpr(_, _) => "Malformed dot expression",
Self::ErrorArithmetic(_, _) => "Arithmetic error",
Self::ErrorRuntime(_, _) => "Runtime error",
Self::ErrorLoopBreak(_) => "Break statement not inside a loop",
Self::Return(_, _) => "[Not Error] Function returns value",
}
}
}
impl Error for EvalAltResult {}
impl fmt::Display for EvalAltResult {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let desc = self.desc();
match self {
Self::ErrorFunctionNotFound(s, pos) => write!(f, "{}: '{}' ({})", desc, s, pos),
Self::ErrorVariableNotFound(s, pos) => write!(f, "{}: '{}' ({})", desc, s, pos),
Self::ErrorIndexingType(_, pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorIndexExpr(pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorLogicGuard(pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorFor(pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorAssignmentToUnknownLHS(pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorAssignmentToConstant(s, pos) => write!(f, "{}: '{}' ({})", desc, s, pos),
Self::ErrorMismatchOutputType(s, pos) => write!(f, "{}: {} ({})", desc, s, pos),
Self::ErrorDotExpr(s, pos) if !s.is_empty() => write!(f, "{} {} ({})", desc, s, pos),
Self::ErrorDotExpr(_, pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorArithmetic(s, pos) => write!(f, "{} ({})", s, pos),
Self::ErrorRuntime(s, pos) => {
write!(f, "{} ({})", if s.is_empty() { desc } else { s }, pos)
}
Self::ErrorLoopBreak(pos) => write!(f, "{} ({})", desc, pos),
Self::Return(_, pos) => write!(f, "{} ({})", desc, pos),
#[cfg(not(feature = "no_std"))]
Self::ErrorReadingScriptFile(path, err) => {
write!(f, "{} '{}': {}", desc, path.display(), err)
}
Self::ErrorParsing(p) => write!(f, "Syntax error: {}", p),
Self::ErrorFunctionArgsMismatch(fun, 0, n, pos) => write!(
f,
"Function '{}' expects no argument but {} found ({})",
fun, n, pos
),
Self::ErrorFunctionArgsMismatch(fun, 1, n, pos) => write!(
f,
"Function '{}' expects one argument but {} found ({})",
fun, n, pos
),
Self::ErrorFunctionArgsMismatch(fun, need, n, pos) => write!(
f,
"Function '{}' expects {} argument(s) but {} found ({})",
fun, need, n, pos
),
Self::ErrorBooleanArgMismatch(op, pos) => {
write!(f, "{} operator expects boolean operands ({})", op, pos)
}
Self::ErrorCharMismatch(pos) => {
write!(f, "string indexing expects a character value ({})", pos)
}
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 ({})",
index, pos
),
Self::ErrorArrayBounds(max, index, pos) => write!(
f,
"Array index {} is out of bounds: only {} elements in the array ({})",
index, max, pos
),
Self::ErrorStringBounds(_, index, pos) if *index < 0 => {
write!(f, "{}: {} < 0 ({})", desc, index, pos)
}
Self::ErrorStringBounds(0, _, pos) => write!(f, "{} ({})", desc, pos),
Self::ErrorStringBounds(1, index, pos) => write!(
f,
"String index {} is out of bounds: only one character in the string ({})",
index, pos
),
Self::ErrorStringBounds(max, index, pos) => write!(
f,
"String index {} is out of bounds: only {} characters in the string ({})",
index, max, pos
),
}
}
}
impl From<ParseError> for EvalAltResult {
fn from(err: ParseError) -> Self {
Self::ErrorParsing(err)
}
}
impl<T: AsRef<str>> From<T> for EvalAltResult {
fn from(err: T) -> Self {
Self::ErrorRuntime(err.as_ref().to_string(), Position::none())
}
}
impl EvalAltResult {
pub fn position(&self) -> Position {
match self {
#[cfg(not(feature = "no_std"))]
Self::ErrorReadingScriptFile(_, _) => Position::none(),
Self::ErrorParsing(err) => err.position(),
Self::ErrorFunctionNotFound(_, pos)
| Self::ErrorFunctionArgsMismatch(_, _, _, pos)
| Self::ErrorBooleanArgMismatch(_, pos)
| Self::ErrorCharMismatch(pos)
| Self::ErrorArrayBounds(_, _, pos)
| Self::ErrorStringBounds(_, _, pos)
| Self::ErrorIndexingType(_, pos)
| Self::ErrorIndexExpr(pos)
| Self::ErrorLogicGuard(pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableNotFound(_, pos)
| Self::ErrorAssignmentToUnknownLHS(pos)
| Self::ErrorAssignmentToConstant(_, pos)
| Self::ErrorMismatchOutputType(_, pos)
| Self::ErrorDotExpr(_, pos)
| Self::ErrorArithmetic(_, pos)
| Self::ErrorRuntime(_, pos)
| Self::ErrorLoopBreak(pos)
| Self::Return(_, pos) => *pos,
}
}
pub(crate) fn set_position(&mut self, new_position: Position) {
match self {
#[cfg(not(feature = "no_std"))]
Self::ErrorReadingScriptFile(_, _) => (),
Self::ErrorParsing(ParseError(_, ref mut pos))
| Self::ErrorFunctionNotFound(_, ref mut pos)
| Self::ErrorFunctionArgsMismatch(_, _, _, ref mut pos)
| Self::ErrorBooleanArgMismatch(_, ref mut pos)
| Self::ErrorCharMismatch(ref mut pos)
| Self::ErrorArrayBounds(_, _, ref mut pos)
| Self::ErrorStringBounds(_, _, ref mut pos)
| Self::ErrorIndexingType(_, ref mut pos)
| Self::ErrorIndexExpr(ref mut pos)
| Self::ErrorLogicGuard(ref mut pos)
| Self::ErrorFor(ref mut pos)
| Self::ErrorVariableNotFound(_, ref mut pos)
| Self::ErrorAssignmentToUnknownLHS(ref mut pos)
| Self::ErrorAssignmentToConstant(_, ref mut pos)
| Self::ErrorMismatchOutputType(_, ref mut pos)
| Self::ErrorDotExpr(_, ref mut pos)
| Self::ErrorArithmetic(_, ref mut pos)
| Self::ErrorRuntime(_, ref mut pos)
| Self::ErrorLoopBreak(ref mut pos)
| Self::Return(_, ref mut pos) => *pos = new_position,
}
}
}