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-rw-r--r--crates/ra_syntax/src/parsing/token_set.rs41
1 files changed, 41 insertions, 0 deletions
diff --git a/crates/ra_syntax/src/parsing/token_set.rs b/crates/ra_syntax/src/parsing/token_set.rs
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index 000000000..5719fe5a2
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+++ b/crates/ra_syntax/src/parsing/token_set.rs
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1use crate::SyntaxKind;
2
3#[derive(Clone, Copy)]
4pub(crate) struct TokenSet(u128);
5
6impl TokenSet {
7 pub(crate) const fn empty() -> TokenSet {
8 TokenSet(0)
9 }
10
11 pub(crate) const fn singleton(kind: SyntaxKind) -> TokenSet {
12 TokenSet(mask(kind))
13 }
14
15 pub(crate) const fn union(self, other: TokenSet) -> TokenSet {
16 TokenSet(self.0 | other.0)
17 }
18
19 pub(crate) fn contains(&self, kind: SyntaxKind) -> bool {
20 self.0 & mask(kind) != 0
21 }
22}
23
24const fn mask(kind: SyntaxKind) -> u128 {
25 1u128 << (kind as usize)
26}
27
28#[macro_export]
29macro_rules! token_set {
30 ($($t:ident),*) => { TokenSet::empty()$(.union(TokenSet::singleton($t)))* };
31 ($($t:ident),* ,) => { token_set!($($t),*) };
32}
33
34#[test]
35fn token_set_works_for_tokens() {
36 use crate::SyntaxKind::*;
37 let ts = token_set! { EOF, SHEBANG };
38 assert!(ts.contains(EOF));
39 assert!(ts.contains(SHEBANG));
40 assert!(!ts.contains(PLUS));
41}