use super::*; pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST .union(paths::PATH_FIRST) .union(token_set![BOX_KW, REF_KW, MUT_KW, L_PAREN, L_BRACK, AMP, UNDERSCORE, MINUS, DOT]); pub(crate) fn pattern(p: &mut Parser) { pattern_r(p, PAT_RECOVERY_SET); } /// Parses a pattern list separated by pipes `|` pub(super) fn pattern_list(p: &mut Parser) { pattern_list_r(p, PAT_RECOVERY_SET) } /// Parses a pattern list separated by pipes `|` /// using the given `recovery_set` pub(super) fn pattern_list_r(p: &mut Parser, recovery_set: TokenSet) { p.eat(T![|]); pattern_r(p, recovery_set); while p.eat(T![|]) { pattern_r(p, recovery_set); } } pub(super) fn pattern_r(p: &mut Parser, recovery_set: TokenSet) { if let Some(lhs) = atom_pat(p, recovery_set) { // test range_pat // fn main() { // match 92 { // 0 ... 100 => (), // 101 ..= 200 => (), // 200 .. 301=> (), // } // } for &range_op in [T![...], T![..=], T![..]].iter() { if p.at(range_op) { let m = lhs.precede(p); p.bump(range_op); atom_pat(p, recovery_set); m.complete(p, RANGE_PAT); return; } } // test marco_pat // fn main() { // let m!(x) = 0; // } if lhs.kind() == PATH_PAT && p.at(T![!]) { let m = lhs.precede(p); items::macro_call_after_excl(p); m.complete(p, MACRO_CALL); } } } const PAT_RECOVERY_SET: TokenSet = token_set![LET_KW, IF_KW, WHILE_KW, LOOP_KW, MATCH_KW, R_PAREN, COMMA]; fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option { let m = match p.nth(0) { T![box] => box_pat(p), T![ref] | T![mut] => bind_pat(p, true), IDENT => match p.nth(1) { // Checks the token after an IDENT to see if a pattern is a path (Struct { .. }) or macro // (T![x]). T!['('] | T!['{'] | T![!] => path_pat(p), T![:] if p.nth_at(1, T![::]) => path_pat(p), _ => bind_pat(p, true), }, _ if paths::is_use_path_start(p) => path_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![&] => ref_pat(p), T!['('] => tuple_pat(p), T!['['] => slice_pat(p), _ => { p.err_recover("expected pattern", recovery_set); return None; } }; Some(m) } fn is_literal_pat_start(p: &Parser) -> bool { p.at(T![-]) && (p.nth(1) == INT_NUMBER || p.nth(1) == FLOAT_NUMBER) || p.at_ts(expressions::LITERAL_FIRST) } // test literal_pattern // fn main() { // match () { // -1 => (), // 92 => (), // 'c' => (), // "hello" => (), // } // } fn literal_pat(p: &mut Parser) -> CompletedMarker { assert!(is_literal_pat_start(p)); let m = p.start(); if p.at(T![-]) { p.bump(T![-]); } expressions::literal(p); m.complete(p, LITERAL_PAT) } // test path_part // fn foo() { // let foo::Bar = (); // let ::Bar = (); // let Bar { .. } = (); // let Bar(..) = (); // } fn path_pat(p: &mut Parser) -> CompletedMarker { assert!(paths::is_use_path_start(p)); let m = p.start(); paths::expr_path(p); let kind = match p.current() { T!['('] => { tuple_pat_fields(p); TUPLE_STRUCT_PAT } T!['{'] => { record_field_pat_list(p); RECORD_PAT } _ => PATH_PAT, }; m.complete(p, kind) } // test tuple_pat_fields // fn foo() { // let S() = (); // let S(_) = (); // let S(_,) = (); // let S(_, .. , x) = (); // } fn tuple_pat_fields(p: &mut Parser) { assert!(p.at(T!['('])); p.bump(T!['(']); pat_list(p, T![')']); p.expect(T![')']); } // test record_field_pat_list // fn foo() { // let S {} = (); // let S { f, ref mut g } = (); // let S { h: _, ..} = (); // let S { h: _, } = (); // } fn record_field_pat_list(p: &mut Parser) { assert!(p.at(T!['{'])); let m = p.start(); p.bump(T!['{']); while !p.at(EOF) && !p.at(T!['}']) { match p.current() { // A trailing `..` is *not* treated as a DOT_DOT_PAT. T![.] if p.at(T![..]) => p.bump(T![..]), IDENT | INT_NUMBER if p.nth(1) == T![:] => record_field_pat(p), T!['{'] => error_block(p, "expected ident"), T![box] => { box_pat(p); } _ => { bind_pat(p, false); } } if !p.at(T!['}']) { p.expect(T![,]); } } p.expect(T!['}']); m.complete(p, RECORD_FIELD_PAT_LIST); } // test record_field_pat // fn foo() { // let S { 0: 1 } = (); // let S { x: 1 } = (); // } fn record_field_pat(p: &mut Parser) { assert!(p.at(IDENT) || p.at(INT_NUMBER)); assert!(p.nth(1) == T![:]); let m = p.start(); if !p.eat(INT_NUMBER) { name(p) } p.bump_any(); pattern(p); m.complete(p, RECORD_FIELD_PAT); } // test placeholder_pat // fn main() { let _ = (); } fn placeholder_pat(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![_])); let m = p.start(); p.bump(T![_]); 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 // fn main() { // let &a = (); // let &mut b = (); // } fn ref_pat(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![&])); let m = p.start(); p.bump(T![&]); p.eat(T![mut]); pattern(p); m.complete(p, REF_PAT) } // test tuple_pat // fn main() { // let (a, b, ..) = (); // } fn tuple_pat(p: &mut Parser) -> CompletedMarker { assert!(p.at(T!['('])); let m = p.start(); tuple_pat_fields(p); m.complete(p, TUPLE_PAT) } // test slice_pat // fn main() { // let [a, b, ..] = []; // } fn slice_pat(p: &mut Parser) -> CompletedMarker { assert!(p.at(T!['['])); let m = p.start(); p.bump(T!['[']); pat_list(p, T![']']); p.expect(T![']']); m.complete(p, SLICE_PAT) } fn pat_list(p: &mut Parser, ket: SyntaxKind) { while !p.at(EOF) && !p.at(ket) { if !p.at_ts(PATTERN_FIRST) { p.error("expected a pattern"); break; } pattern(p); if !p.at(ket) { p.expect(T![,]); } } } // test bind_pat // fn main() { // let a = (); // let mut b = (); // let ref c = (); // let ref mut d = (); // let e @ _ = (); // let ref mut f @ g @ _ = (); // } fn bind_pat(p: &mut Parser, with_at: bool) -> CompletedMarker { let m = p.start(); p.eat(T![ref]); p.eat(T![mut]); name(p); if with_at && p.eat(T![@]) { pattern(p); } m.complete(p, BIND_PAT) } // test box_pat // fn main() { // let box i = (); // let box Outer { box i, j: box Inner(box &x) } = (); // let box ref mut i = (); // } fn box_pat(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![box])); let m = p.start(); p.bump(T![box]); pattern(p); m.complete(p, BOX_PAT) }