Enum rustc_expand::mbe::macro_parser::MatcherLoc

source · [−]
pub(super) enum MatcherLoc {
    Token {
        token: Token,
    },
    Delimited,
    Sequence {
        op: KleeneOp,
        num_metavar_decls: usize,
        idx_first_after: usize,
        next_metavar: usize,
        seq_depth: usize,
    },
    SequenceKleeneOpNoSep {
        op: KleeneOp,
        idx_first: usize,
    },
    SequenceSep {
        separator: Token,
    },
    SequenceKleeneOpAfterSep {
        idx_first: usize,
    },
    MetaVarDecl {
        span: Span,
        bind: Ident,
        kind: Option<NonterminalKind>,
        next_metavar: usize,
        seq_depth: usize,
    },
    Eof,
}
Expand description

A unit within a matcher that a MatcherPos can refer to. Similar to (and derived from) mbe::TokenTree, but designed specifically for fast and easy traversal during matching. Notable differences to mbe::TokenTree:

  • It is non-recursive, i.e. there is no nesting.
  • The end pieces of each sequence (the separator, if present, and the Kleene op) are represented explicitly, as is the very end of the matcher.

This means a matcher can be represented by &[MatcherLoc], and traversal mostly involves simply incrementing the current matcher position index by one.

Variants

Token

Fields

token: Token

Delimited

Sequence

Fields

op: KleeneOp
num_metavar_decls: usize
idx_first_after: usize
next_metavar: usize
seq_depth: usize

SequenceKleeneOpNoSep

Fields

op: KleeneOp
idx_first: usize

SequenceSep

Fields

separator: Token

SequenceKleeneOpAfterSep

Fields

idx_first: usize

MetaVarDecl

Fields

span: Span
bind: Ident
kind: Option<NonterminalKind>
next_metavar: usize
seq_depth: usize

Eof

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

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: 40 bytes

Size for each variant:

  • Token: 31 bytes
  • Delimited: 0 bytes
  • Sequence: 39 bytes
  • SequenceKleeneOpNoSep: 15 bytes
  • SequenceSep: 31 bytes
  • SequenceKleeneOpAfterSep: 15 bytes
  • MetaVarDecl: 39 bytes
  • Eof: 0 bytes