Struct Stateful

pub struct Stateful<I, S> {
    pub input: I,
    pub state: S,
}

Thread global state through your parsers

Use cases

• Recursion checks
• Error recovery
• Debugging

Example

#[derive(Debug)]
struct State<'s>(&'s mut u32);

impl<'s> State<'s> {
    fn count(&mut self) {
        *self.0 += 1;
    }
}

type Stream<'is> = Stateful<&'is str, State<'is>>;

fn word<'s>(i: &mut Stream<'s>) -> PResult<&'s str> {
  i.state.count();
  alpha1.parse_next(i)
}

let data = "Hello";
let mut state = 0;
let input = Stream { input: data, state: State(&mut state) };
let output = word.parse(input).unwrap();
assert_eq!(state, 1);

Fields

input: I

Inner input being wrapped in state

state: S

User-provided state

Trait Implementations

impl<I, S> AsBStr for Stateful<I, S>

where I: AsBStr,

fn as_bstr(&self) -> &[u8]

Casts the input type to a byte slice

impl<I, S> AsBytes for Stateful<I, S>

where I: AsBytes,

fn as_bytes(&self) -> &[u8]

Casts the input type to a byte slice

impl<I, S> AsRef<I> for Stateful<I, S>

fn as_ref(&self) -> &I

Converts this type into a shared reference of the (usually inferred) input type.

impl<I: Clone, S: Clone> Clone for Stateful<I, S>

fn clone(&self) -> Stateful<I, S>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<I, S, U> Compare<U> for Stateful<I, S>

where I: Compare<U>,

fn compare(&self, other: U) -> CompareResult

Compares self to another value for equality

impl<I: Debug, S: Debug> Debug for Stateful<I, S>

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

Formats the value using the given formatter.

impl<I: Default, S: Default> Default for Stateful<I, S>

fn default() -> Stateful<I, S>

Returns the “default value” for a type.

impl<I, S> Deref for Stateful<I, S>

type Target = I

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<I: Display, S> Display for Stateful<I, S>

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

Formats the value using the given formatter.

impl<I, S, T> FindSlice<T> for Stateful<I, S>

where I: FindSlice<T>,

fn find_slice(&self, substr: T) -> Option<Range<usize>>

Returns the offset of the slice if it is found

impl<I, S> Location for Stateful<I, S>

where I: Location,

fn location(&self) -> usize

Number of indices input has advanced since start of parsing

impl<I, S> Offset<<Stateful<I, S> as Stream>::Checkpoint> for Stateful<I, S>

where I: Stream, S: Debug,

fn offset_from(&self, other: &<Stateful<I, S> as Stream>::Checkpoint) -> usize

Offset between the first byte of start and the first byte of selfa

impl<I, S> Offset for Stateful<I, S>

where I: Stream, S: Clone + Debug,

fn offset_from(&self, start: &Self) -> usize

Offset between the first byte of start and the first byte of selfa

impl<I: PartialEq, S: PartialEq> PartialEq for Stateful<I, S>

fn eq(&self, other: &Stateful<I, S>) -> 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<I, E, S> Recover<E> for Stateful<I, S>

where I: Recover<E> + Stream, S: Clone + Debug,

Available on crate features unstable-recover and std only.

fn is_recovery_supported() -> bool

Report whether the Stream can save off errors for recovery

fn record_err( &mut self, _token_start: &Self::Checkpoint, _err_start: &Self::Checkpoint, err: ErrMode<E>, ) -> Result<(), ErrMode<E>>

Capture a top-level error

impl<I, S> SliceLen for Stateful<I, S>

where I: SliceLen,

fn slice_len(&self) -> usize

Calculates the input length, as indicated by its name, and the name of the trait itself

impl<I: Stream, S: Debug> Stream for Stateful<I, S>

type Token = <I as Stream>::Token

The smallest unit being parsed

type Slice = <I as Stream>::Slice

Sequence of Tokens

type IterOffsets = <I as Stream>::IterOffsets

Iterate with the offset from the current location

type Checkpoint = Checkpoint<<I as Stream>::Checkpoint, Stateful<I, S>>

A parse location within the stream

fn iter_offsets(&self) -> Self::IterOffsets

Iterate with the offset from the current location

fn eof_offset(&self) -> usize

Returns the offset to the end of the input

fn next_token(&mut self) -> Option<Self::Token>

Split off the next token from the input

fn offset_for<P>(&self, predicate: P) -> Option<usize>

where P: Fn(Self::Token) -> bool,

Finds the offset of the next matching token

fn offset_at(&self, tokens: usize) -> Result<usize, Needed>

Get the offset for the number of tokens into the stream

fn next_slice(&mut self, offset: usize) -> Self::Slice

Split off a slice of tokens from the input

fn checkpoint(&self) -> Self::Checkpoint

Save the current parse location within the stream

fn reset(&mut self, checkpoint: &Self::Checkpoint)

Revert the stream to a prior Self::Checkpoint

fn raw(&self) -> &dyn Debug

Return the inner-most stream

fn finish(&mut self) -> Self::Slice

Advance to the end of the stream

impl<I, S> StreamIsPartial for Stateful<I, S>

where I: StreamIsPartial,

type PartialState = <I as StreamIsPartial>::PartialState

Whether the stream is currently partial or complete

fn complete(&mut self) -> Self::PartialState

Mark the stream is complete

fn restore_partial(&mut self, state: Self::PartialState)

Restore the stream back to its previous state

fn is_partial_supported() -> bool

Report whether the Stream is can ever be incomplete

fn is_partial(&self) -> bool

Report whether the Stream is currently incomplete

impl<I, S> UpdateSlice for Stateful<I, S>

where I: UpdateSlice, S: Clone + Debug,

fn update_slice(self, inner: Self::Slice) -> Self

Convert an Output type to be used as Stream

impl<I: Copy, S: Copy> Copy for Stateful<I, S>

impl<I: Eq, S: Eq> Eq for Stateful<I, S>

impl<I, S> StructuralPartialEq for Stateful<I, S>