rhai/src/result.rs

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//! Module containing error definitions for the evaluation process.
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use crate::stdlib::{
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boxed::Box,
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error::Error,
fmt,
string::{String, ToString},
};
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use crate::{Dynamic, ImmutableString, ParseErrorType, Position, INT};
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/// Evaluation result.
///
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/// All wrapped [`Position`] values represent the location in the script where the error occurs.
///
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/// # Thread Safety
///
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/// Currently, [`EvalAltResult`] is neither [`Send`] nor [`Sync`].
/// Turn on the `sync` feature to make it [`Send`] `+` [`Sync`].
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#[derive(Debug)]
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#[non_exhaustive]
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pub enum EvalAltResult {
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/// System error. Wrapped values are the error message and the internal error.
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#[cfg(not(feature = "sync"))]
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ErrorSystem(String, Box<dyn Error>),
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/// System error. Wrapped values are the error message and the internal error.
#[cfg(feature = "sync")]
ErrorSystem(String, Box<dyn Error + Send + Sync>),
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/// Syntax error.
ErrorParsing(ParseErrorType, Position),
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/// Usage of an unknown variable. Wrapped value is the variable name.
ErrorVariableNotFound(String, Position),
/// Call to an unknown function. Wrapped value is the function signature.
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ErrorFunctionNotFound(String, Position),
/// An error has occurred inside a called function.
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/// Wrapped values are the function name, function source, and the interior error.
ErrorInFunctionCall(String, String, Box<EvalAltResult>, Position),
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/// Usage of an unknown [module][crate::Module]. Wrapped value is the [module][crate::Module] name.
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ErrorModuleNotFound(String, Position),
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/// An error has occurred while loading a [module][crate::Module].
/// Wrapped value are the [module][crate::Module] name and the interior error.
ErrorInModule(String, Box<EvalAltResult>, Position),
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/// Access to `this` that is not bound.
ErrorUnboundThis(Position),
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/// Data is not of the required type.
/// Wrapped values are the type requested and type of the actual result.
ErrorMismatchDataType(String, String, Position),
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/// Returned type is not the same as the required output type.
/// Wrapped values are the type requested and type of the actual result.
ErrorMismatchOutputType(String, String, Position),
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/// Array access out-of-bounds.
/// Wrapped values are the current number of elements in the array and the index number.
ErrorArrayBounds(usize, INT, Position),
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/// String indexing out-of-bounds.
/// Wrapped values are the current number of characters in the string and the index number.
ErrorStringBounds(usize, INT, Position),
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/// Trying to index into a type that is not an array, an object map, or a string, and has no
/// indexer function defined. Wrapped value is the type name.
ErrorIndexingType(String, Position),
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/// Invalid arguments for `in` operator.
ErrorInExpr(Position),
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/// The `for` statement encounters a type that is not an iterator.
ErrorFor(Position),
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/// Data race detected when accessing a variable. Wrapped value is the variable name.
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ErrorDataRace(String, Position),
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/// Assignment to a constant variable. Wrapped value is the variable name.
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ErrorAssignmentToConstant(String, Position),
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/// Inappropriate property access. Wrapped value is the property name.
ErrorDotExpr(String, Position),
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/// Arithmetic error encountered. Wrapped value is the error message.
ErrorArithmetic(String, Position),
/// Number of operations over maximum limit.
ErrorTooManyOperations(Position),
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/// [Modules][crate::Module] over maximum limit.
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ErrorTooManyModules(Position),
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/// Call stack over maximum limit.
ErrorStackOverflow(Position),
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/// Data value over maximum size limit. Wrapped value is the type name.
ErrorDataTooLarge(String, Position),
/// The script is prematurely terminated. Wrapped value is the termination token.
ErrorTerminated(Dynamic, Position),
/// Run-time error encountered. Wrapped value is the error token.
ErrorRuntime(Dynamic, Position),
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/// Breaking out of loops - not an error if within a loop.
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/// The wrapped value, if true, means breaking clean out of the loop (i.e. a `break` statement).
/// The wrapped value, if false, means breaking the current context (i.e. a `continue` statement).
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LoopBreak(bool, Position),
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/// Not an error: Value returned from a script via the `return` keyword.
/// Wrapped value is the result value.
Return(Dynamic, Position),
}
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impl EvalAltResult {
pub(crate) fn desc(&self) -> &str {
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match self {
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#[allow(deprecated)]
Self::ErrorSystem(_, s) => s.description(),
Self::ErrorParsing(p, _) => p.desc(),
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Self::ErrorInFunctionCall(_,_, _, _) => "Error in called function",
Self::ErrorInModule(_, _, _) => "Error in module",
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Self::ErrorFunctionNotFound(_, _) => "Function not found",
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Self::ErrorUnboundThis(_) => "'this' is not bound",
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Self::ErrorMismatchDataType(_, _, _) => "Data type is incorrect",
Self::ErrorIndexingType(_, _) => {
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"Indexing can only be performed on an array, an object map, a string, or a type with an indexer function defined"
}
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Self::ErrorArrayBounds(_, index, _) if *index < 0 => {
"Array access expects non-negative index"
}
Self::ErrorArrayBounds(0, _, _) => "Empty array has nothing to access",
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Self::ErrorArrayBounds(_, _, _) => "Array index out of bounds",
Self::ErrorStringBounds(_, index, _) if *index < 0 => {
"Indexing a string expects a non-negative index"
}
Self::ErrorStringBounds(0, _, _) => "Empty string has nothing to index",
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Self::ErrorStringBounds(_, _, _) => "String index out of bounds",
Self::ErrorFor(_) => "For loop expects an array, object map, or range",
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Self::ErrorVariableNotFound(_, _) => "Variable not found",
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Self::ErrorModuleNotFound(_, _) => "Module not found",
Self::ErrorDataRace(_, _) => "Data race detected when accessing variable",
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Self::ErrorAssignmentToConstant(_, _) => "Cannot assign to a constant",
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Self::ErrorMismatchOutputType(_, _, _) => "Output type is incorrect",
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Self::ErrorInExpr(_) => "Malformed 'in' expression",
Self::ErrorDotExpr(_, _) => "Malformed dot expression",
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Self::ErrorArithmetic(_, _) => "Arithmetic error",
Self::ErrorTooManyOperations(_) => "Too many operations",
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Self::ErrorTooManyModules(_) => "Too many modules imported",
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Self::ErrorStackOverflow(_) => "Stack overflow",
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Self::ErrorDataTooLarge(_, _) => "Data size exceeds maximum limit",
Self::ErrorTerminated(_,_) => "Script terminated.",
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Self::ErrorRuntime(_, _) => "Runtime error",
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Self::LoopBreak(true, _) => "Break statement not inside a loop",
Self::LoopBreak(false, _) => "Continue statement not inside a loop",
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Self::Return(_, _) => "[Not Error] Function returns value",
}
}
}
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impl Error for EvalAltResult {}
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impl fmt::Display for EvalAltResult {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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let desc = self.desc();
let pos = self.position();
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match self {
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Self::ErrorSystem(s, _) if s.is_empty() => f.write_str(desc)?,
Self::ErrorSystem(s, _) => write!(f, "{}: {}", s, desc)?,
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Self::ErrorParsing(p, _) => write!(f, "Syntax error: {}", p)?,
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#[cfg(not(feature = "no_function"))]
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Self::ErrorInFunctionCall(s, src, err, _) if crate::engine::is_anonymous_fn(s) => {
write!(f, "{}, in call to closure", err)?;
if !src.is_empty() {
write!(f, " @ '{}'", src)?;
}
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}
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Self::ErrorInFunctionCall(s, src, err, _) => {
write!(f, "{}, in call to function {}", err, s)?;
if !src.is_empty() {
write!(f, " @ '{}'", src)?;
}
}
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Self::ErrorInModule(s, err, _) if s.is_empty() => {
write!(f, "Error in module: {}", err)?
}
Self::ErrorInModule(s, err, _) => write!(f, "Error in module '{}': {}", s, err)?,
Self::ErrorFunctionNotFound(s, _)
| Self::ErrorVariableNotFound(s, _)
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| Self::ErrorDataRace(s, _) => write!(f, "{}: {}", desc, s)?,
Self::ErrorModuleNotFound(s, _) => write!(f, "{}: '{}'", desc, s)?,
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Self::ErrorDotExpr(s, _) if !s.is_empty() => write!(f, "{}", s)?,
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Self::ErrorIndexingType(_, _)
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| Self::ErrorUnboundThis(_)
| Self::ErrorFor(_)
| Self::ErrorInExpr(_)
| Self::ErrorDotExpr(_, _)
| Self::ErrorTooManyOperations(_)
| Self::ErrorTooManyModules(_)
| Self::ErrorStackOverflow(_)
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| Self::ErrorTerminated(_, _) => f.write_str(desc)?,
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Self::ErrorRuntime(d, _) if d.is::<ImmutableString>() => {
let s = d.as_str().unwrap();
write!(f, "{}: {}", desc, if s.is_empty() { desc } else { s })?
}
Self::ErrorRuntime(d, _) if d.is::<()>() => f.write_str(desc)?,
Self::ErrorRuntime(d, _) => write!(f, "{}: {}", desc, d)?,
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Self::ErrorAssignmentToConstant(s, _) => write!(f, "Cannot assign to constant {}", s)?,
Self::ErrorMismatchOutputType(s, r, _) => {
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write!(f, "Output type is incorrect: {} (expecting {})", r, s)?
}
Self::ErrorMismatchDataType(s, r, _) if r.is_empty() => {
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write!(f, "Data type is incorrect, expecting {}", s)?
}
Self::ErrorMismatchDataType(s, r, _) if s.is_empty() => {
write!(f, "Data type is incorrect: {}", r)?
}
Self::ErrorMismatchDataType(s, r, _) => {
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write!(f, "Data type is incorrect: {} (expecting {})", r, s)?
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}
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Self::ErrorArithmetic(s, _) => f.write_str(s)?,
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Self::LoopBreak(_, _) => f.write_str(desc)?,
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Self::Return(_, _) => f.write_str(desc)?,
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Self::ErrorArrayBounds(_, index, _) if *index < 0 => {
write!(f, "{}: {} < 0", desc, index)?
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}
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Self::ErrorArrayBounds(0, _, _) => f.write_str(desc)?,
Self::ErrorArrayBounds(1, index, _) => write!(
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f,
"Array index {} is out of bounds: only one element in the array",
index
)?,
Self::ErrorArrayBounds(max, index, _) => write!(
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f,
"Array index {} is out of bounds: only {} elements in the array",
index, max
)?,
Self::ErrorStringBounds(_, index, _) if *index < 0 => {
write!(f, "{}: {} < 0", desc, index)?
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}
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Self::ErrorStringBounds(0, _, _) => f.write_str(desc)?,
Self::ErrorStringBounds(1, index, _) => write!(
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f,
"String index {} is out of bounds: only one character in the string",
index
)?,
Self::ErrorStringBounds(max, index, _) => write!(
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f,
"String index {} is out of bounds: only {} characters in the string",
index, max
)?,
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Self::ErrorDataTooLarge(typ, _) => write!(f, "{} exceeds maximum limit", typ)?,
}
// Do not write any position if None
if !pos.is_none() {
write!(f, " ({})", pos)?;
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}
Ok(())
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}
}
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impl<T: AsRef<str>> From<T> for EvalAltResult {
#[inline(always)]
fn from(err: T) -> Self {
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Self::ErrorRuntime(err.as_ref().to_string().into(), Position::NONE)
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}
}
impl<T: AsRef<str>> From<T> for Box<EvalAltResult> {
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#[inline(always)]
fn from(err: T) -> Self {
Box::new(EvalAltResult::ErrorRuntime(
err.as_ref().to_string().into(),
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Position::NONE,
))
}
}
impl EvalAltResult {
/// Can this error be caught?
///
/// # Panics
///
/// Panics when [`LoopBreak`][EvalAltResult::LoopBreak] or [`Return`][EvalAltResult::Return].
pub fn is_catchable(&self) -> bool {
match self {
Self::ErrorSystem(_, _) => false,
Self::ErrorParsing(_, _) => false,
Self::ErrorFunctionNotFound(_, _)
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| Self::ErrorInFunctionCall(_, _, _, _)
| Self::ErrorInModule(_, _, _)
| Self::ErrorUnboundThis(_)
| Self::ErrorMismatchDataType(_, _, _)
| Self::ErrorArrayBounds(_, _, _)
| Self::ErrorStringBounds(_, _, _)
| Self::ErrorIndexingType(_, _)
| Self::ErrorFor(_)
| Self::ErrorVariableNotFound(_, _)
| Self::ErrorModuleNotFound(_, _)
| Self::ErrorDataRace(_, _)
| Self::ErrorAssignmentToConstant(_, _)
| Self::ErrorMismatchOutputType(_, _, _)
| Self::ErrorInExpr(_)
| Self::ErrorDotExpr(_, _)
| Self::ErrorArithmetic(_, _)
| Self::ErrorRuntime(_, _) => true,
Self::ErrorTooManyOperations(_)
| Self::ErrorTooManyModules(_)
| Self::ErrorStackOverflow(_)
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| Self::ErrorDataTooLarge(_, _)
| Self::ErrorTerminated(_, _) => false,
Self::LoopBreak(_, _) => panic!("EvalAltResult::LoopBreak should not occur naturally"),
Self::Return(_, _) => panic!("EvalAltResult::Return should not occur naturally"),
}
}
/// Is this error a system exception?
///
/// # Panics
///
/// Panics when [`LoopBreak`][EvalAltResult::LoopBreak] or [`Return`][EvalAltResult::Return].
pub fn is_system_exception(&self) -> bool {
match self {
Self::ErrorSystem(_, _) => true,
Self::ErrorParsing(_, _) => true,
Self::ErrorTooManyOperations(_)
| Self::ErrorTooManyModules(_)
| Self::ErrorStackOverflow(_)
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| Self::ErrorDataTooLarge(_, _) => true,
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Self::ErrorTerminated(_, _) => true,
Self::LoopBreak(_, _) => panic!("EvalAltResult::LoopBreak should not occur naturally"),
Self::Return(_, _) => panic!("EvalAltResult::Return should not occur naturally"),
_ => false,
}
}
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/// Get the [position][Position] of this error.
pub fn position(&self) -> Position {
match self {
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Self::ErrorSystem(_, _) => Position::NONE,
Self::ErrorParsing(_, pos)
| Self::ErrorFunctionNotFound(_, pos)
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| Self::ErrorInFunctionCall(_, _, _, pos)
| Self::ErrorInModule(_, _, pos)
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| Self::ErrorUnboundThis(pos)
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| Self::ErrorMismatchDataType(_, _, pos)
| Self::ErrorArrayBounds(_, _, pos)
| Self::ErrorStringBounds(_, _, pos)
| Self::ErrorIndexingType(_, pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableNotFound(_, pos)
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| Self::ErrorModuleNotFound(_, pos)
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| Self::ErrorDataRace(_, pos)
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| Self::ErrorAssignmentToConstant(_, pos)
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| Self::ErrorMismatchOutputType(_, _, pos)
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| Self::ErrorInExpr(pos)
| Self::ErrorDotExpr(_, pos)
| Self::ErrorArithmetic(_, pos)
| Self::ErrorTooManyOperations(pos)
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| Self::ErrorTooManyModules(pos)
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| Self::ErrorStackOverflow(pos)
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| Self::ErrorDataTooLarge(_, pos)
| Self::ErrorTerminated(_, pos)
| Self::ErrorRuntime(_, pos)
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| Self::LoopBreak(_, pos)
| Self::Return(_, pos) => *pos,
}
}
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/// Clear the [position][Position] information of this error.
pub fn clear_position(&mut self) -> &mut Self {
self.set_position(Position::NONE);
self
}
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/// Override the [position][Position] of this error.
pub fn set_position(&mut self, new_position: Position) {
match self {
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Self::ErrorSystem(_, _) => (),
Self::ErrorParsing(_, pos)
| Self::ErrorFunctionNotFound(_, pos)
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| Self::ErrorInFunctionCall(_, _, _, pos)
| Self::ErrorInModule(_, _, pos)
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| Self::ErrorUnboundThis(pos)
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| Self::ErrorMismatchDataType(_, _, pos)
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| Self::ErrorArrayBounds(_, _, pos)
| Self::ErrorStringBounds(_, _, pos)
| Self::ErrorIndexingType(_, pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableNotFound(_, pos)
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| Self::ErrorModuleNotFound(_, pos)
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| Self::ErrorDataRace(_, pos)
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| Self::ErrorAssignmentToConstant(_, pos)
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| Self::ErrorMismatchOutputType(_, _, pos)
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| Self::ErrorInExpr(pos)
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| Self::ErrorDotExpr(_, pos)
| Self::ErrorArithmetic(_, pos)
| Self::ErrorTooManyOperations(pos)
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| Self::ErrorTooManyModules(pos)
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| Self::ErrorStackOverflow(pos)
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| Self::ErrorDataTooLarge(_, pos)
| Self::ErrorTerminated(_, pos)
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| Self::ErrorRuntime(_, pos)
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| Self::LoopBreak(_, pos)
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| Self::Return(_, pos) => *pos = new_position,
}
}
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/// Consume the current [`EvalAltResult`] and return a new one with the specified [`Position`]
/// if the current position is [`Position::None`].
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#[inline(always)]
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pub(crate) fn fill_position(mut self: Box<Self>, new_position: Position) -> Box<Self> {
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if self.position().is_none() {
self.set_position(new_position);
}
self
}
}
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impl<T> From<EvalAltResult> for Result<T, Box<EvalAltResult>> {
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#[inline(always)]
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fn from(err: EvalAltResult) -> Self {
Err(err.into())
}
}