Function eval_expression_function

pub fn eval_expression_function<'a>(
    ast: &AstExpr,
    param_names: &[Cow<'a, str>],
    arg_values: &[Real],
    parent_ctx: Option<Rc<EvalContext<'a>>>,
) -> Result<Real>

Evaluates an expression function with the given arguments.

This is a helper function used internally by the evaluation logic.