Struct Discard 

pub struct Discard<T>(/* private fields */);

Succeeds when the next token matches T. The token will be removed from the stream but not stored. Consequently the ToTokens implementations will panic with a message that it can not be emitted. This can only be used when a token should be present but not stored and never emitted.

Example

let mut token_iter = "ident ()".to_token_iter();

let _ = Discard::<Ident>::parse(&mut token_iter).unwrap();
assert!(ParenthesisGroup::parse(&mut token_iter).is_ok());

Trait Implementations

impl<T> Clone for Discard<T>

where T: Clone,

fn clone(&self) -> Discard<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Discard<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T> Parser for Discard<T>

where T: Parse,

fn parser( tokens: &mut ShadowCountedIter<'_, <TokenStream as IntoIterator>::IntoIter>, ) -> Result<Discard<T>, Error>

The actual parsing function that must be implemented. This mutates the tokens iterator directly. It should not be called from user code except for implementing parsers itself and then only when the rules below are followed.

impl<T> ToTokens for Discard<T>

fn to_tokens(&self, _tokens: &mut TokenStream)

Write &self to the given TokenStream.

fn to_token_iter( &self, ) -> ShadowCountedIter<'_, <TokenStream as IntoIterator>::IntoIter>

Convert &self into a TokenIter object.

fn into_token_iter<'a>( self, ) -> ShadowCountedIter<'a, <TokenStream as IntoIterator>::IntoIter>

where Self: Sized,

Convert self into a TokenIter object.

fn to_token_stream(&self) -> TokenStream

Convert &self into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self into a TokenStream object.

fn tokens_to_string(&self) -> String

Convert &self into a String object. This is mostly used in the test suite to compare the outputs. When the input is a &str then this parses it and returns a normalized String.