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Parse .. as a proper pattern

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This commit is contained in:
Dylan MacKenzie 2019-09-14 17:06:08 -07:00
parent 426112c97e
commit 4a3a15f0e7
1 changed files with 42 additions and 10 deletions
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52
crates/ra_parser/src/grammar/patterns.rs
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@ -2,7 +2,7 @@ use super::*;
pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST
.union(paths::PATH_FIRST) .union(paths::PATH_FIRST)
.union(token_set![BOX_KW, REF_KW, MUT_KW, L_PAREN, L_BRACK, AMP, UNDERSCORE, MINUS]); .union(token_set![BOX_KW, REF_KW, MUT_KW, L_PAREN, L_BRACK, AMP, UNDERSCORE, MINUS, DOT]);
pub(crate) fn pattern(p: &mut Parser) { pub(crate) fn pattern(p: &mut Parser) {
pattern_r(p, PAT_RECOVERY_SET); pattern_r(p, PAT_RECOVERY_SET);
@ -73,6 +73,7 @@ fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
_ if paths::is_use_path_start(p) => path_pat(p), _ if paths::is_use_path_start(p) => path_pat(p),
_ if is_literal_pat_start(p) => literal_pat(p), _ if is_literal_pat_start(p) => literal_pat(p),
T![.] if p.at(T![..]) => dot_dot_pat(p),
T![_] => placeholder_pat(p), T![_] => placeholder_pat(p),
T![&] => ref_pat(p), T![&] => ref_pat(p),
T!['('] => tuple_pat(p), T!['('] => tuple_pat(p),
@ -163,7 +164,9 @@ fn record_field_pat_list(p: &mut Parser) {
p.bump_any(); p.bump_any();
while !p.at(EOF) && !p.at(T!['}']) { while !p.at(EOF) && !p.at(T!['}']) {
match p.current() { match p.current() {
// A trailing `..` is *not* treated as a DOT_DOT_PAT.
T![.] if p.at(T![..]) => p.bump(T![..]), T![.] if p.at(T![..]) => p.bump(T![..]),
IDENT if p.nth(1) == T![:] => record_field_pat(p), IDENT if p.nth(1) == T![:] => record_field_pat(p),
T!['{'] => error_block(p, "expected ident"), T!['{'] => error_block(p, "expected ident"),
T![box] => { T![box] => {
@ -201,6 +204,39 @@ fn placeholder_pat(p: &mut Parser) -> CompletedMarker {
m.complete(p, PLACEHOLDER_PAT) m.complete(p, PLACEHOLDER_PAT)
} }
// test dot_dot_pat
// fn main() {
// let .. = ();
// //
// // Tuples
// //
// let (a, ..) = ();
// let (a, ..,) = ();
// let Tuple(a, ..) = ();
// let Tuple(a, ..,) = ();
// let (.., ..) = ();
// let Tuple(.., ..) = ();
// let (.., a, ..) = ();
// let Tuple(.., a, ..) = ();
// //
// // Slices
// //
// let [..] = ();
// let [head, ..] = ();
// let [head, tail @ ..] = ();
// let [head, .., cons] = ();
// let [head, mid @ .., cons] = ();
// let [head, .., .., cons] = ();
// let [head, .., mid, tail @ ..] = ();
// let [head, .., mid, .., cons] = ();
// }
fn dot_dot_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![..]));
let m = p.start();
p.bump(T![..]);
m.complete(p, DOT_DOT_PAT)
}
// test ref_pat // test ref_pat
// fn main() { // fn main() {
// let &a = (); // let &a = ();
@ -241,16 +277,12 @@ fn slice_pat(p: &mut Parser) -> CompletedMarker {
fn pat_list(p: &mut Parser, ket: SyntaxKind) { fn pat_list(p: &mut Parser, ket: SyntaxKind) {
while !p.at(EOF) && !p.at(ket) { while !p.at(EOF) && !p.at(ket) {
match p.current() { if !p.at_ts(PATTERN_FIRST) {
T![.] if p.at(T![..]) => p.bump(T![..]), p.error("expected a pattern");
_ => { break;
if !p.at_ts(PATTERN_FIRST) {
p.error("expected a pattern");
break;
}
pattern(p)
}
} }
pattern(p);
if !p.at(ket) { if !p.at(ket) {
p.expect(T![,]); p.expect(T![,]);
} }