Enum fasteval::error::Error

pub enum Error {
    SlabOverflow,
    AlreadyExists,
    EOF,
    EofWhileParsing(String),
    Utf8ErrorWhileParsing(String),
    TooLong,
    TooDeep,
    UnparsedTokensRemaining(String),
    InvalidValue,
    ParseF64(String),
    Expected(String),
    WrongArgs(String),
    Undefined(String),
    Unreachable,
}

This is the error type used in fasteval's Results.

For performance reasons, fasteval makes an effort to always return Errors instead of using panic!().

Variants

SlabOverflow

Too many Expressions/Values/Instructions were stored in the Slab.

A Slab is pre-allocated at the beginning of the process, and it is not re-sized. You can use Slab::with_capacity() to increase the number of items that can be stored.

AlreadyExists

Returned by EvalNamespace::create_cached().

An entry with the same name already exists in the Namespace. If you intend to overwrite existing entries, use EvalNamespace::set_cached()` instead.

EOF

Reached an unexpected End Of Input during parsing.

EofWhileParsing(String)

Reached an unexpected End Of Input during parsing.

The String field contains information about what was being parsed when the EOF was reached.

Utf8ErrorWhileParsing(String)

UTF8 decoding error.

The String field contains information about what was being parsed when the UTF8 error occurred.

TooLong

The expression string input was too long.

This is a safety check that prevents malicious inputs that would be expensive to parse.

TooDeep

The expression was too recursive.

This is a safety check that prevents malicious inputs that would be expensive to parse.

UnparsedTokensRemaining(String)

An expression was parsed, but there is still input data remaining.

The String field contains the un-parsed input data.

InvalidValue

A value was expected, but invalid input data was found.

ParseF64(String)

An error occurred during the parsing of a f64 number.

The String field contains the data that caused the error.

Expected(String)

The expected input data was not found.

The String field tells you what was expected.

WrongArgs(String)

A function was called with the wrong arguments.

The String field contains information about the expected arguments.

Undefined(String)

The expression tried to use an undefined variable/function.

You can define variables/functions with a Namespace.

Unreachable

This error should never occur because it is only produced by code paths that should never execute. This is more performant than using the unreachable!() macro.

Trait Implementations

impl Clone for Error

fn clone(&self) -> Error

Returns a copy 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<(), Error>

Formats the value using the given formatter.

impl Error for Error

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

The lower-level source of this error, if any.

fn backtrace(&self) -> Option<&Backtrace>

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

Returns a stack backtrace, if available, of where this error occurred.

fn description(&self) -> &str

Deprecated since 1.41.0:

use the Display impl or to_string()

if let Err(e) = "xc".parse::<u32>() { // Print e itself, no need for description(). eprintln!("Error: {}", e); }

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

Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

impl PartialEq<Error> for Error

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl StructuralPartialEq for Error