Struct ExpressionError 

pub struct ExpressionError { /* private fields */ }

Base error for expression evaluation.

Wraps an ExpressionErrorKind with optional source location context for caret-style error formatting.

Internally boxed (8 bytes on stack) to keep Result<ExprValue, ExpressionError> compact. Same pattern as serde_json::Error.

Implementations

impl ExpressionError

pub fn from_kind(kind: ExpressionErrorKind) -> Self

Create an error from a structured kind.

pub fn new(message: impl Into<String>) -> Self

Create an error with a plain message string.

This is a convenience for call sites that don’t need a structured kind. Prefer ExpressionError::from_kind with a specific variant when the error category is known.

pub fn integer_overflow() -> Self

Integer overflow error.

pub fn division_by_zero(op: &'static str) -> Self

Division or modulo by zero.

pub fn float_error(message: impl Into<String>) -> Self

Float produced infinity or NaN.

pub fn type_error(message: impl Into<String>) -> Self

Type mismatch error.

pub fn index_out_of_bounds(message: impl Into<String>) -> Self

Index out of bounds.

pub fn unsupported(feature: impl Into<String>) -> Self

Unsupported Python syntax feature.

pub fn explicit_fail(message: impl Into<String>) -> Self

Explicit fail() call.

pub fn parse_error(message: impl Into<String>) -> Self

A parse-stage error (underlying parser, range expression parser, etc.).

pub fn expression_too_deep(depth: usize, limit: usize) -> Self

AST nesting depth exceeded the configured limit.

pub fn kind(&self) -> &ExpressionErrorKind

The structured error kind.

pub fn message(&self) -> String

The human-readable error message (the Display output of the kind).

pub fn sub_errors(&self) -> &[ExpressionError]

Sub-errors for compound failures (e.g., both branches of an if/else).

pub fn with_sub_errors(self, sub_errors: Vec<ExpressionError>) -> Self

Attach sub-errors (consumes and returns self for chaining).

pub fn expr(&self) -> Option<&str>

The expression source text, if attached.

pub fn col_offset(&self) -> Option<usize>

The start column offset within the expression, if attached.

pub fn end_col_offset(&self) -> Option<usize>

The end column offset within the expression, if attached.

pub fn caret_offset(&self) -> Option<usize>

The caret offset relative to col_offset, if attached.

pub fn with_node(self, expr_source: &str, node: &Expr) -> Self

Attach expression source and AST node span for caret formatting.

pub fn with_span(self, expr_source: &str, col: usize, end_col: usize) -> Self

Attach expression source with explicit span (no AST node).

pub fn set_source_span( &mut self, expr_source: &str, col: usize, end_col: usize, caret_offset: usize, )

Set the expression source and span directly (for cases where with_node cannot be used because the span is computed manually).

pub fn message_with_expr_prefix(&self, prefix: &str) -> String

Format the error with a prefix prepended to the expression line.

The caret position is shifted right by prefix.len() so it still points at the correct column in the combined prefix + expr string. Used for let-binding errors where the expression is part of a larger construct like "x = Param.Frame + \"oops\"".

Only applies to single-line expressions with caret indicators. Falls back to the normal Display output for multi-line or context-free errors.

Trait Implementations

impl Clone for ExpressionError

fn clone(&self) -> ExpressionError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExpressionError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for ExpressionError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for ExpressionError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<RangeExprError> for ExpressionError

fn from(e: RangeExprError) -> Self

Lift a range-expression parse error into an ExpressionError.

If the error carries a position, attach the source string with a span covering the single character at that offset so the standard caret renderer points at the failure. Without a position, fall back to the stringified Display form.

impl From<SymbolTableError> for ExpressionError

fn from(e: SymbolTableError) -> Self

Bubble a symbol-table conflict up as an ExpressionError::Other.

The full SymbolTableError message is preserved verbatim so callers can still see which key was being set and what it conflicted with. Call sites that have an AST node available can further attach .with_node(...) / .with_span(...) for caret-annotated output.