Enum EvalError 

pub enum EvalError {
    UnknownFunction(QName),
    UnboundVariable(QName),
    ArgumentCount {
        function: &'static str,
        expected: usize,
        got: usize,
    },
    ExpectedNodeSet {
        context: &'static str,
    },
}

An evaluation-time error. Distinct from ParseError (parser.rs), which covers syntax — this covers semantic failures once a well-formed Expr is evaluated against a concrete context.

Variants

UnknownFunction(QName)

PrimaryExpr::Function named something other than one of the 27 implemented core-library functions (last/position/count, Phase 04, plus the 24 more in functions.rs, Phase 05 — including id(), see its doc comment there).

UnboundVariable(QName)

PrimaryExpr::Variable has no binding via the context’s lookup hook.

ArgumentCount

A function called with the wrong number of arguments.

Fields

function: &'static str

expected: usize

got: usize

ExpectedNodeSet

count()’s argument, or a Union/FilterExpr-predicate operand, did not evaluate to a node-set.

Fields

context: &'static str

Trait Implementations

impl Clone for EvalError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EvalError

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

Formats the value using the given formatter.

impl Display for EvalError

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

Formats the value using the given formatter.

impl Error for EvalError

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 PartialEq for EvalError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for EvalError