Enum ParseError

pub enum ParseError<L, T, E> {
    InvalidToken {
        location: L,
    },
    UnrecognizedEof {
        location: L,
        expected: Vec<String>,
    },
    UnrecognizedToken {
        token: (L, T, L),
        expected: Vec<String>,
    },
    ExtraToken {
        token: (L, T, L),
    },
    User {
        error: E,
    },
}

Error type for errors returned by lalrpop parsers.

For the built-in lexer, the generic parameters default to: ParseError<usize, lexer::Token<’_>, &’static str>.

L: the location of the Token where the error occurred T: The token encountered where the error occurred E: A custom user-defined error

L and T are fixed types as listed above for built in lexers, and can be defined to whatever type you would like if implementing a custom lexer.

The type of E can be overridden by specifying type Error in your grammar like so:

extern {
    type Error = MyCustomErrorType;
}

Variants

InvalidToken

Generated by the internal lexer when it encounters a token (or EOF) it did not expect.

Fields

location: L

The end of the invalid token.

UnrecognizedEof

Generated by the parser when it encounters an EOF it did not expect.

Fields

location: L

The end of the final token.

expected: Vec<String>

The set of expected tokens: these names are taken from the grammar and hence may not necessarily be suitable for presenting to the user.

UnrecognizedToken

Generated by the parser when it encounters a token it did not expect.

This means that the next token in the stream was not valid at this point in the grammar.

Fields

token: (L, T, L)

The unexpected token of type T with a span given by the two L values.

expected: Vec<String>

The set of expected tokens: these names are taken from the grammar and hence may not necessarily be suitable for presenting to the user.

ExtraToken

Generated by the parser when it encounters additional, unexpected tokens.

Fields

token: (L, T, L)

The extra token, with a type of T with a span given by the two L values.

User

Custom error type.

Fields

error: E

Custom user error.

Implementations

impl<L, T, E> ParseError<L, T, E>

pub fn map_location<LL>(self, op: impl FnMut(L) -> LL) -> ParseError<LL, T, E>

Transform a ParseError by applying a function to the location field.

This could be useful to ensure that all fields implement some trait, or to apply an offset to a location.

(Note that unlike map_token() and map_error(), the closure argument for this function is FnMut. This is so that it can be called multiple times to apply to the starting and ending location of tokens.)

pub fn map_token<TT>(self, op: impl FnOnce(T) -> TT) -> ParseError<L, TT, E>

Transform a ParseError by applying a function to the token field.

This could be useful to ensure that all fields implement some trait, or to transform a token in some way (eg escaping).

pub fn map_error<EE>(self, op: impl FnOnce(E) -> EE) -> ParseError<L, T, EE>

Transform a ParseError by applying a function to the error field.

This could be useful to ensure that all fields implement some trait, or to transform to a different error type in place.

Trait Implementations

impl<L: Clone, T: Clone, E: Clone> Clone for ParseError<L, T, E>

fn clone(&self) -> ParseError<L, T, E>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<L: Debug, T: Debug, E: Debug> Debug for ParseError<L, T, E>

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

Formats the value using the given formatter.

impl<L, T, E> Display for ParseError<L, T, E>

where L: Display, T: Display, E: Display,

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

Formats the value using the given formatter.

impl<L, T, E> Error for ParseError<L, T, E>

where L: Debug + Display, T: Debug + Display, E: Debug + Display,

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

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

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

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<L, T, E> From<E> for ParseError<L, T, E>

fn from(error: E) -> Self

Converts to this type from the input type.

impl<L: Ord, T: Ord, E: Ord> Ord for ParseError<L, T, E>

fn cmp(&self, other: &ParseError<L, T, E>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<L: PartialEq, T: PartialEq, E: PartialEq> PartialEq for ParseError<L, T, E>

fn eq(&self, other: &ParseError<L, T, E>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<L: PartialOrd, T: PartialOrd, E: PartialOrd> PartialOrd for ParseError<L, T, E>

fn partial_cmp(&self, other: &ParseError<L, T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<L: Eq, T: Eq, E: Eq> Eq for ParseError<L, T, E>

impl<L, T, E> StructuralPartialEq for ParseError<L, T, E>