Struct mentat_parser_utils::value_and_span::OfExactly

pub struct OfExactly<P, N>(_, _);

OfExactly and of_exactly allow us to express nested parsers naturally.

For example, vector().of_exactly(many(list())) parses a vector-of-lists, like [(1 2) (:a :b) ("test") ()].

The "outer" parser P and the "nested" parser N must be compatible: P must produce an output edn::ValueAndSpan which can itself be turned into a stream of child elements; and N must accept the resulting input Stream. This compatibility allows us to lift errors from the nested parser to the outer parser, which is part of what has made parsing &'a [edn::Value] difficult.

Trait Implementations

impl<P: Clone, N: Clone> Clone for OfExactly<P, N>

fn clone(&self) -> OfExactly<P, N>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a, P, N, M, O> Parser for OfExactly<P, N> where     P: Parser<Input = Stream<'a>, Output = M>,     N: Parser<Input = Stream<'a>, Output = O>,     M: 'a + Streaming<'a>,

type Input = P::Input

The type which is taken as input for the parser. The type must implement the Stream trait which allows the parser to read items from the type.

type Output = O

The type which is returned if the parser is successful.

fn parse_lazy(     &mut self,     input: Self::Input ) -> ConsumedResult<Self::Output, Self::Input>

Parses using the stream input by calling [Stream::uncons] one or more times.

fn add_error(&mut self, errors: &mut ParseError<Self::Input>)

Adds the first error that would normally be returned by this parser if it failed with an EmptyErr result.

fn parse(     &mut self,     input: Self::Input ) -> Result<(Self::Output, Self::Input), ParseError<Self::Input>>

Entry point of the parser. Takes some input and tries to parse it.

fn parse_stream(     &mut self,     input: Self::Input ) -> Result<(Self::Output, Consumed<Self::Input>), Consumed<ParseError<Self::Input>>>

Parses using the stream input by calling [Stream::uncons] one or more times.

fn parse_stream_consumed(     &mut self,     input: Self::Input ) -> FastResult<(Self::Output, Self::Input), ParseError<Self::Input>>

Parses using the stream input by calling [Stream::uncons] one or more times.

fn by_ref(&mut self) -> &mut Self

Borrows a parser instead of consuming it.

fn with<P2>(self, p: P2) -> With<Self, P2> where     P2: Parser<Input = Self::Input>,

Discards the value of the self parser and returns the value of p. Fails if any of the parsers fails.

fn skip<P2>(self, p: P2) -> Skip<Self, P2> where     P2: Parser<Input = Self::Input>,

Discards the value of the p parser and returns the value of self. Fails if any of the parsers fails.

fn and<P2>(self, p: P2) -> (Self, P2) where     P2: Parser<Input = Self::Input>,

Parses with self followed by p. Succeeds if both parsers succeed, otherwise fails. Returns a tuple with both values on success.

fn or<P2>(self, p: P2) -> Or<Self, P2> where     P2: Parser<Input = Self::Input, Output = Self::Output>,

Returns a parser which attempts to parse using self. If self fails without consuming any input it tries to consume the same input using p.

fn then<N, F>(self, f: F) -> Then<Self, F> where     F: FnMut(Self::Output) -> N,     N: Parser<Input = Self::Input>,

Parses using self and then passes the value to f which returns a parser used to parse the rest of the input.

fn map<F, B>(self, f: F) -> Map<Self, F> where     F: FnMut(Self::Output) -> B,

Uses f to map over the parsed value.

fn flat_map<F, B>(self, f: F) -> FlatMap<Self, F> where     F: FnMut(Self::Output) -> Result<B, ParseError<Self::Input>>,

Uses f to map over the output of self. If f returns an error the parser fails.

fn message<S>(self, msg: S) -> Message<Self> where     S: Into<Info<<Self::Input as StreamOnce>::Item, <Self::Input as StreamOnce>::Range>>,

Parses with self and if it fails, adds the message msg to the error.

fn expected<S>(self, msg: S) -> Expected<Self> where     S: Into<Info<<Self::Input as StreamOnce>::Item, <Self::Input as StreamOnce>::Range>>,

Parses with self and if it fails without consuming any input any expected errors are replaced by msg. msg is then used in error messages as "Expected msg".

fn and_then<F, O, E>(self, f: F) -> AndThen<Self, F> where     E: Into<Error<<Self::Input as StreamOnce>::Item, <Self::Input as StreamOnce>::Range>>,     F: FnMut(Self::Output) -> Result<O, E>,

Parses with self and applies f on the result if self parses successfully. f may optionally fail with an error which is automatically converted to a ParseError.

fn iter(self, input: Self::Input) -> Iter<Self>

Creates an iterator from a parser and a state. Can be used as an alternative to [many] when collecting directly into a FromIterator type is not desirable.

fn boxed<'a>(     self ) -> Box<Parser<Input = Self::Input, Output = Self::Output> + 'a> where     Self: 'a,

Turns the parser into a trait object by putting it in a Box. Can be used to easily return parsers from functions without naming the type.