Enum syntax::ext::tt::quoted::TokenTree

pub enum TokenTree {
    Token(Token),
    Delimited(DelimSpan, Lrc<Delimited>),
    Sequence(DelimSpan, Lrc<SequenceRepetition>),
    MetaVar(Span, Ident),
    MetaVarDecl(Span, Ident, Ident),
}

Similar to tokenstream::TokenTree, except that $i, $i:ident, and $(...) are "first-class" token trees. Useful for parsing macros.

Variants

Token(Token)Delimited(DelimSpan, Lrc<Delimited>)Sequence(DelimSpan, Lrc<SequenceRepetition>)

A kleene-style repetition sequence

MetaVar(Span, Ident)

e.g., $var

MetaVarDecl(Span, Ident, Ident)

e.g., $var:expr. This is only used in the left hand side of MBE macros.

Methods

impl TokenTree

pub fn len(&self) -> usize

Return the number of tokens in the tree.

pub fn is_empty(&self) -> bool

Returns true if the given token tree contains no other tokens. This is vacuously true for single tokens or metavar/decls, but may be false for delimited trees or sequences.

pub fn is_delimited(&self) -> bool

Returns true if the given token tree is delimited.

pub fn is_token(&self, expected_kind: &TokenKind) -> bool

Returns true if the given token tree is a token of the given kind.

pub fn get_tt(&self, index: usize) -> TokenTree

Gets the index-th sub-token-tree. This only makes sense for delimited trees and sequences.

pub fn span(&self) -> Span

Retrieves the TokenTree's span.

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 PartialEq<TokenTree> for TokenTree

fn eq(&self, other: &TokenTree) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &TokenTree) -> bool

This method tests for !=.

impl Debug for TokenTree

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

Formats the value using the given formatter.

impl Encodable for TokenTree

fn encode<__S: Encoder>(&self, s: &mut __S) -> Result<(), __S::Error>

impl Decodable for TokenTree

fn decode<__D: Decoder>(d: &mut __D) -> Result<TokenTree, __D::Error>