rhai/src/result.rs

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//! Module containing error definitions for the evaluation process.
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use crate::any::Dynamic;
use crate::error::ParseErrorType;
use crate::parser::INT;
use crate::token::Position;
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use crate::stdlib::{
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boxed::Box,
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error::Error,
fmt,
string::{String, ToString},
};
#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
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use crate::stdlib::path::PathBuf;
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/// Evaluation result.
///
/// All wrapped `Position` values represent the location in the script where the error occurs.
///
/// 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 {
/// Syntax error.
ErrorParsing(ParseErrorType, Position),
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/// Error reading from a script file. Wrapped value is the path of the script file.
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///
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/// Never appears under the `no_std` feature.
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#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
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ErrorReadingScriptFile(PathBuf, Position, std::io::Error),
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/// Call to an unknown function. Wrapped value is the name of the function.
ErrorFunctionNotFound(String, Position),
/// An error has occurred inside a called function.
/// Wrapped values re the name of the function and the interior error.
ErrorInFunctionCall(String, Box<EvalAltResult>, Position),
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/// Access to `this` that is not bounded.
ErrorUnboundedThis(Position),
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/// 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),
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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.
ErrorIndexingType(String, Position),
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/// Trying to index into an array or string with an index that is not `i64`.
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ErrorNumericIndexExpr(Position),
/// Trying to index into a map with an index that is not `String`.
ErrorStringIndexExpr(Position),
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/// Trying to import with an expression that is not `String`.
ErrorImportExpr(Position),
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/// Invalid arguments for `in` operator.
ErrorInExpr(Position),
/// The guard expression in an `if` or `while` statement does not return a boolean value.
ErrorLogicGuard(Position),
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/// 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),
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/// Usage of an unknown module. Wrapped value is the name of the module.
ErrorModuleNotFound(String, Position),
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/// Assignment to an inappropriate LHS (left-hand-side) expression.
ErrorAssignmentToUnknownLHS(Position),
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/// Assignment to a constant variable.
ErrorAssignmentToConstant(String, Position),
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/// Returned type is not the same as the required output type.
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/// Wrapped values are the type requested and type of the actual result.
ErrorMismatchOutputType(String, String, Position),
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/// Inappropriate member access.
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 over maximum limit.
ErrorTooManyModules(Position),
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/// Call stack over maximum limit.
ErrorStackOverflow(Position),
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/// Data value over maximum size limit. Wrapped values are the data type, maximum size and current size.
ErrorDataTooLarge(String, usize, usize, Position),
/// The script is prematurely terminated.
ErrorTerminated(Position),
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/// Run-time error encountered. Wrapped value is the error message.
ErrorRuntime(String, 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).
ErrorLoopBreak(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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#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
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Self::ErrorReadingScriptFile(_, _, _) => "Cannot read from script file",
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Self::ErrorParsing(p, _) => p.desc(),
Self::ErrorInFunctionCall(_, _, _) => "Error in called function",
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Self::ErrorFunctionNotFound(_, _) => "Function not found",
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Self::ErrorUnboundedThis(_) => "'this' is not bounded",
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Self::ErrorBooleanArgMismatch(_, _) => "Boolean operator expects boolean operands",
Self::ErrorCharMismatch(_) => "Character expected",
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Self::ErrorNumericIndexExpr(_) => {
"Indexing into an array or string expects an integer index"
}
Self::ErrorStringIndexExpr(_) => "Indexing into an object map expects a string index",
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::ErrorImportExpr(_) => "Importing a module expects a string path",
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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::ErrorLogicGuard(_) => "Boolean value expected",
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",
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Self::ErrorAssignmentToUnknownLHS(_) => {
"Assignment to an unsupported left-hand side expression"
}
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Self::ErrorAssignmentToConstant(_, _) => "Assignment to a constant variable",
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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::ErrorLoopBreak(true, _) => "Break statement not inside a loop",
Self::ErrorLoopBreak(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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#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
Self::ErrorReadingScriptFile(path, _, err) => {
write!(f, "{} '{}': {}", desc, path.display(), err)?
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}
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Self::ErrorParsing(p, _) => write!(f, "Syntax error: {}", p)?,
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Self::ErrorInFunctionCall(s, err, _) => {
write!(f, "Error in call to function '{}' : {}", s, err)?
}
Self::ErrorFunctionNotFound(s, _)
| Self::ErrorVariableNotFound(s, _)
| Self::ErrorModuleNotFound(s, _) => write!(f, "{}: '{}'", desc, s)?,
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Self::ErrorDotExpr(s, _) if !s.is_empty() => write!(f, "{} {}", desc, s)?,
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Self::ErrorIndexingType(_, _)
| Self::ErrorNumericIndexExpr(_)
| Self::ErrorStringIndexExpr(_)
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| Self::ErrorUnboundedThis(_)
| Self::ErrorImportExpr(_)
| Self::ErrorLogicGuard(_)
| Self::ErrorFor(_)
| Self::ErrorAssignmentToUnknownLHS(_)
| 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(s, _) => f.write_str(if s.is_empty() { desc } else { s })?,
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Self::ErrorAssignmentToConstant(s, _) => write!(f, "{}: '{}'", desc, s)?,
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Self::ErrorMismatchOutputType(r, s, _) => {
write!(f, "{} (expecting {}): {}", desc, s, r)?
}
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Self::ErrorArithmetic(s, _) => f.write_str(s)?,
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Self::ErrorLoopBreak(_, _) => f.write_str(desc)?,
Self::Return(_, _) => f.write_str(desc)?,
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Self::ErrorBooleanArgMismatch(op, _) => {
write!(f, "{} operator expects boolean operands", op)?
}
Self::ErrorCharMismatch(_) => write!(f, "string indexing expects a character value")?,
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, max, size, _) => {
write!(f, "{} ({}) exceeds the maximum limit ({})", typ, size, max)?
}
}
// Do not write any position if None
if !pos.is_none() {
write!(f, " ({})", pos)?;
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}
Ok(())
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}
}
impl<T: AsRef<str>> From<T> for Box<EvalAltResult> {
fn from(err: T) -> Self {
Box::new(EvalAltResult::ErrorRuntime(
err.as_ref().to_string(),
Position::none(),
))
}
}
impl EvalAltResult {
/// Get the `Position` of this error.
pub fn position(&self) -> Position {
match self {
#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
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Self::ErrorReadingScriptFile(_, pos, _) => *pos,
Self::ErrorParsing(_, pos)
| Self::ErrorFunctionNotFound(_, pos)
| Self::ErrorInFunctionCall(_, _, pos)
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| Self::ErrorUnboundedThis(pos)
| Self::ErrorBooleanArgMismatch(_, pos)
| Self::ErrorCharMismatch(pos)
| Self::ErrorArrayBounds(_, _, pos)
| Self::ErrorStringBounds(_, _, pos)
| Self::ErrorIndexingType(_, pos)
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| Self::ErrorNumericIndexExpr(pos)
| Self::ErrorStringIndexExpr(pos)
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| Self::ErrorImportExpr(pos)
| Self::ErrorLogicGuard(pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableNotFound(_, pos)
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| Self::ErrorModuleNotFound(_, pos)
| Self::ErrorAssignmentToUnknownLHS(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::ErrorLoopBreak(_, pos)
| Self::Return(_, pos) => *pos,
}
}
/// Override the `Position` of this error.
pub fn set_position(&mut self, new_position: Position) {
match self {
#[cfg(not(feature = "no_std"))]
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#[cfg(not(target_arch = "wasm32"))]
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Self::ErrorReadingScriptFile(_, pos, _) => *pos = new_position,
Self::ErrorParsing(_, pos)
| Self::ErrorFunctionNotFound(_, pos)
| Self::ErrorInFunctionCall(_, _, pos)
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| Self::ErrorUnboundedThis(pos)
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| Self::ErrorBooleanArgMismatch(_, pos)
| Self::ErrorCharMismatch(pos)
| Self::ErrorArrayBounds(_, _, pos)
| Self::ErrorStringBounds(_, _, pos)
| Self::ErrorIndexingType(_, pos)
| Self::ErrorNumericIndexExpr(pos)
| Self::ErrorStringIndexExpr(pos)
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| Self::ErrorImportExpr(pos)
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| Self::ErrorLogicGuard(pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableNotFound(_, pos)
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| Self::ErrorModuleNotFound(_, pos)
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| Self::ErrorAssignmentToUnknownLHS(pos)
| 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)
| Self::ErrorLoopBreak(_, pos)
| 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`.
pub(crate) fn new_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
}
}