Enum Error 

pub enum Error {
    Parse {
        message: String,
        pos: usize,
    },
    Unknown {
        name: String,
    },
    Missing {
        name: String,
    },
    OutOfRange {
        index: i64,
        len: usize,
    },
    Type {
        operation: &'static str,
        got: &'static str,
    },
    Overflow {
        operation: &'static str,
    },
    DivideByZero {
        operation: &'static str,
    },
    Function {
        name: String,
        message: String,
    },
    UnknownMethod {
        name: String,
    },
    Convert {
        message: String,
    },
}

Everything acts-expr can fail with.

A parse error carries the byte offset in the source it stopped at; an evaluation error names the operation and the value type it could not apply to, because the same expression can be valid for one context and not for the next.

Variants

Parse

The source is not a well-formed expression.

Fields

message: String

pos: usize

Unknown

An identifier is not in the context.

Fields

name: String

Missing

A member of an object (or an index of a list) does not exist.

Fields

name: String

OutOfRange

A list index is negative or past the end, with the length it was read against.

Fields

index: i64

len: usize

Type

An operand or receiver has no type for the operation.

Fields

operation: &'static str

The operation as it reads in the source, e.g. '+' or '<'.

got: &'static str

The value’s type: null, int, float, string, bool, list, map or function.

Overflow

An arithmetic operation overflowed an i64.

Fields

operation: &'static str

DivideByZero

A division or remainder had a zero divisor.

Fields

operation: &'static str

Function

A native function (an injected method) failed.

Fields

name: String

message: String

UnknownMethod

The receiver of a method call is not an object and no function of that name is in the context.

Fields

name: String

Convert

A value could not cross the json bridge.

Fields

message: String

Implementations

impl Error

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

The byte offset a parse error stopped at, for a host that wants to point at it. None for every error raised at evaluation time.

Trait Implementations

impl Clone for Error

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 Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Eq for Error

impl Error for Error

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 Error

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Error