Struct proc_macro2::TokenStream

[+] Show declaration

pub struct TokenStream { /* fields omitted */ }

[−] Expand description

An abstract stream of tokens, or more concretely a sequence of token trees.

This type provides interfaces for iterating over token trees and for collecting token trees into one stream.

Token stream is both the input and output of #[proc_macro], #[proc_macro_attribute] and #[proc_macro_derive] definitions.

Methods

impl TokenStream

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pub fn new() -> TokenStream

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Returns an empty TokenStream containing no token trees.

pub fn empty() -> TokenStream

Deprecated since 0.4.4

: please use TokenStream::new

pub fn is_empty(&self) -> bool

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Checks if this TokenStream is empty.

Trait Implementations

impl IntoIterator for TokenStream

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type Item = TokenTree

The type of the elements being iterated over.

type IntoIter = IntoIter

Which kind of iterator are we turning this into?

Important traits for IntoIter

impl Iterator for IntoIter type Item = TokenTree;

fn into_iter(self) -> IntoIter

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Creates an iterator from a value.

impl Clone for TokenStream

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fn clone(&self) -> TokenStream

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Returns a copy of the value.

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

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Performs copy-assignment from source.

impl Default for TokenStream

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TokenStream::default() returns an empty stream, i.e. this is equivalent with TokenStream::new().

fn default() -> Self

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Returns the "default value" for a type.

impl FromStr for TokenStream

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Attempts to break the string into tokens and parse those tokens into a token stream.

May fail for a number of reasons, for example, if the string contains unbalanced delimiters or characters not existing in the language.

NOTE: Some errors may cause panics instead of returning LexError. We reserve the right to change these errors into LexErrors later.

type Err = LexError

The associated error which can be returned from parsing.

fn from_str(src: &str) -> Result<TokenStream, LexError>

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Parses a string s to return a value of this type.

impl From<TokenStream> for TokenStream

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fn from(inner: TokenStream) -> TokenStream

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Performs the conversion.

impl From<TokenStream> for TokenStream

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fn from(inner: TokenStream) -> TokenStream

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Performs the conversion.

impl Extend<TokenTree> for TokenStream

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fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I)

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Extends a collection with the contents of an iterator.

impl Extend<TokenStream> for TokenStream

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fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I)

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Extends a collection with the contents of an iterator.

impl FromIterator<TokenTree> for TokenStream

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Collects a number of token trees into a single stream.

fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self

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Creates a value from an iterator.

impl Display for TokenStream

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Prints the token stream as a string that is supposed to be losslessly convertible back into the same token stream (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters and negative numeric literals.

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

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Formats the value using the given formatter.

impl Debug for TokenStream

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Prints token in a form convenient for debugging.

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

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Formats the value using the given formatter.