Enum TokenTree

enum TokenTree {
    Token(Token),
    Delimited(DelimSpan, DelimSpacing, Delimited),
    Sequence(DelimSpan, SequenceRepetition),
    MetaVar(Span, Ident),
    MetaVarDecl(Span, Ident, Option<NonterminalKind>),
    MetaVarExpr(DelimSpan, MetaVarExpr),
}

Similar to tokenstream::TokenTree, except that Sequence, MetaVar, MetaVarDecl, and MetaVarExpr are “first-class” token trees. Useful for parsing macros.

Variants

Token(Token)

A token. Unlike tokenstream::TokenTree::Token this lacks a Spacing. See the comments about Spacing in the transcribe function.

Delimited(DelimSpan, DelimSpacing, Delimited)

A delimited sequence, e.g. ($e:expr) (RHS) or { $e } (LHS).

Sequence(DelimSpan, SequenceRepetition)

A kleene-style repetition sequence, e.g. $($e:expr)* (RHS) or $($e),* (LHS).

MetaVar(Span, Ident)

e.g., $var. The span covers the leading dollar and the ident. (The span within the ident only covers the ident, e.g. var.)

MetaVarDecl(Span, Ident, Option<NonterminalKind>)

e.g., $var:expr. Only appears on the LHS.

MetaVarExpr(DelimSpan, MetaVarExpr)

A meta-variable expression inside ${...}.

Implementations

impl TokenTree

fn is_delimited(&self) -> bool

Returns true if the given token tree is delimited.

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

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

fn span(&self) -> Span

Retrieves the TokenTree’s span.

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

Trait Implementations

impl Debug for TokenTree

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

Formats the value using the given formatter.

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

fn decode(__decoder: &mut __D) -> Self

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

fn encode(&self, __encoder: &mut __E)

impl PartialEq for TokenTree

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

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: 88 bytes

Size for each variant:

• Token: 32 bytes
• Delimited: 64 bytes
• Sequence: 88 bytes
• MetaVar: 28 bytes
• MetaVarDecl: 32 bytes
• MetaVarExpr: 48 bytes