Enum proc_macro::TokenTree

pub enum TokenTree {
    Group(Group),
    Ident(Ident),
    Punct(Punct),
    Literal(Literal),
}

A single token or a delimited sequence of token trees (e.g., [1, (), ..]).

Variants

Group(Group)

A token stream surrounded by bracket delimiters.

Ident(Ident)

An identifier.

Punct(Punct)

A single punctuation character (+, ,, $, etc.).

Literal(Literal)

A literal character ('a'), string ("hello"), number (2.3), etc.

Implementations

impl TokenTree

pub fn span(&self) -> Span

Returns the span of this tree, delegating to the span method of the contained token or a delimited stream.

pub fn set_span(&mut self, span: Span)

Configures the span for only this token.

Note that if this token is a Group then this method will not configure the span of each of the internal tokens, this will simply delegate to the set_span method of each variant.

Trait Implementations

impl Clone for TokenTree

fn clone(&self) -> TokenTree

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TokenTree

Prints token tree in a form convenient for debugging.

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

Formats the value using the given formatter.

impl Display for TokenTree

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

Note: the exact form of the output is subject to change, e.g. there might be changes in the whitespace used between tokens. Therefore, you should not do any kind of simple substring matching on the output string (as produced by to_string) to implement a proc macro, because that matching might stop working if such changes happen. Instead, you should work at the TokenTree level, e.g. matching against TokenTree::Ident, TokenTree::Punct, or TokenTree::Literal.

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

Formats the value using the given formatter.

impl Extend<TokenTree> for TokenStream

fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: 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 #72631)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one #72631)

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

impl From<Group> for TokenTree

fn from(g: Group) -> TokenTree

Converts to this type from the input type.

impl From<Ident> for TokenTree

fn from(g: Ident) -> TokenTree

Converts to this type from the input type.

impl From<Literal> for TokenTree

fn from(g: Literal) -> TokenTree

Converts to this type from the input type.

impl From<Punct> for TokenTree

fn from(g: Punct) -> TokenTree

Converts to this type from the input type.

impl From<TokenTree> for TokenStream

Creates a token stream containing a single token tree.

fn from(tree: TokenTree) -> TokenStream

Converts to this type from the input type.

impl FromIterator<TokenTree> for TokenStream

Collects a number of token trees into a single stream.

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

Creates a value from an iterator.

impl !Send for TokenTree

impl !Sync for TokenTree