Struct winnow::stream::Stateful

source ·
pub struct Stateful<I, S> {
    pub input: I,
    pub state: S,
}
Expand description

Thread global state through your parsers

Use cases

  • Recursion checks
  • Error recovery
  • Debugging

Example


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

impl<'s> State<'s> {
    fn count(&self) {
        self.0.set(self.0.get() + 1);
    }
}

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

fn word(i: Stream<'_>) -> IResult<Stream<'_>, &str> {
  i.state.count();
  alpha1(i)
}

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

Fields§

§input: I

Inner input being wrapped in state

§state: S

User-provided state

Trait Implementations§

Casts the input type to a byte slice
Casts the input type to a byte slice
Converts this type into a shared reference of the (usually inferred) input type.
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Compares self to another value for equality
Compares self to another value for equality independently of the case. Read more
Formats the value using the given formatter. Read more
The resulting type after dereferencing.
Dereferences the value.
Formats the value using the given formatter. Read more
Returns the offset of the slice if it is found
Number of indices input has advanced since start of parsing
Offset between the first byte of self and the first byte of the argument
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Calculates the input length, as indicated by its name, and the name of the trait itself
The smallest unit being parsed Read more
Sequence of Tokens Read more
Iterate with the offset from the current location
Iterate with the offset from the current location
Returns the offaet to the end of the input
Split off the next token from the input
Finds the offset of the next matching token
Get the offset for the number of tokens into the stream Read more
Split off a slice of tokens from the input Read more
Whether the stream is currently partial or complete
Mark the stream is complete
Restore the stream back to its previous state
Report whether the Stream is can ever be incomplete
Report whether the Stream is currently incomplete
Convert an Output type to be used as Stream

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.