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
SequenceKleeneOpNoSep
SequenceSep
Fields
separator: Token
SequenceKleeneOpAfterSep
Fields
idx_first: usize
MetaVarDecl
Eof
Auto Trait Implementations
impl !RefUnwindSafe for MatcherLoc
impl !Send for MatcherLoc
impl !Sync for MatcherLoc
impl Unpin for MatcherLoc
impl !UnwindSafe for MatcherLoc
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
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 bytesDelimited
: 0 bytesSequence
: 39 bytesSequenceKleeneOpNoSep
: 15 bytesSequenceSep
: 31 bytesSequenceKleeneOpAfterSep
: 15 bytesMetaVarDecl
: 39 bytesEof
: 0 bytes