Enum rustc_ast::tokenstream::TokenTree

pub enum TokenTree {
    Token(Token),
    Delimited(DelimSpan, DelimToken, TokenStream),
}

When the main Rust parser encounters a syntax-extension invocation, it parses the arguments to the invocation as a token tree. This is a very loose structure, such that all sorts of different AST fragments can be passed to syntax extensions using a uniform type.

If the syntax extension is an MBE macro, it will attempt to match its LHS token tree against the provided token tree, and if it finds a match, will transcribe the RHS token tree, splicing in any captured macro_parser::matched_nonterminals into the SubstNts it finds.

The RHS of an MBE macro is the only place SubstNts are substituted. Nothing special happens to misnamed or misplaced SubstNts.

Variants

Token(Token)

A single token.

Tuple Fields of Token

0: Token

Delimited(DelimSpan, DelimToken, TokenStream)

A delimited sequence of token trees.

Tuple Fields of Delimited

0: DelimSpan1: DelimToken2: TokenStream

Implementations

impl TokenTree

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

Checks if this TokenTree is equal to the other, regardless of span information.

pub fn span(&self) -> Span

Retrieves the TokenTree’s span.

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

Modify the TokenTree’s span in-place.

pub fn token(kind: TokenKind, span: Span) -> TokenTree

pub fn open_tt(span: DelimSpan, delim: DelimToken) -> TokenTree

Returns the opening delimiter as a token tree.

pub fn close_tt(span: DelimSpan, delim: DelimToken) -> TokenTree

Returns the closing delimiter as a token tree.

pub fn uninterpolate(self) -> TokenTree

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

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

Formats the value using the given formatter.

impl<__D: Decoder> Decodable<__D> for TokenTree

fn decode(__decoder: &mut __D) -> Result<Self, <__D as Decoder>::Error>

impl<__E: Encoder> Encodable<__E> for TokenTree

fn encode(&self, __encoder: &mut __E) -> Result<(), <__E as Encoder>::Error>

impl From<TokenTree> for TokenStream

fn from(tree: TokenTree) -> TokenStream

Performs the conversion.

impl From<TokenTree> for TreeAndSpacing

fn from(tree: TokenTree) -> TreeAndSpacing

Performs the conversion.

impl FromIterator<TokenTree> for TokenStream

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

Creates a value from an iterator.

impl<__CTX> HashStable<__CTX> for TokenTree where
    __CTX: HashStableContext, 

fn hash_stable(&self, __hcx: &mut __CTX, __hasher: &mut StableHasher)

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 StructuralPartialEq for TokenTree

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes

Size for each variant:

• Token: 31 bytes
• Delimited: 31 bytes