Struct TokenStream

pub struct TokenStream { /* private fields */ }

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.

Implementations

impl TokenStream

pub fn new() -> Self

Returns an empty TokenStream containing no token trees.

pub fn is_empty(&self) -> bool

Checks if this TokenStream is empty.

Trait Implementations

impl Clone for TokenStream

fn clone(&self) -> TokenStream

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TokenStream

Prints token in a form convenient for debugging.

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

Formats the value using the given formatter.

impl Default for TokenStream

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

fn default() -> Self

Returns the “default value” for a type.

impl Display for TokenStream

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

Formats the value using the given formatter.

impl Extend<TokenStream> for TokenStream

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

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Extend<TokenTree> for TokenStream

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

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl From<TokenStream> for TokenStream

Available on crate feature proc-macro only.

fn from(inner: TokenStream) -> Self

Converts to this type from the input type.

impl From<TokenStream> for TokenStream

Available on crate feature proc-macro only.

fn from(inner: TokenStream) -> Self

Converts to this type from the input type.

impl From<TokenTree> for TokenStream

fn from(token: TokenTree) -> Self

Converts to this type from the input type.

impl FromIterator<TokenStream> for TokenStream

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

Creates a value from an iterator.

impl FromIterator<TokenTree> for TokenStream

Collects a number of token trees into a single stream.

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

Creates a value from an iterator.

impl FromStr for TokenStream

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>

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

impl IntoIterator for TokenStream

type Item = TokenTree

The type of the elements being iterated over.

type IntoIter = IntoIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> IntoIter

Creates an iterator from a value.