Unnamed repository; edit this file 'description' to name the repository.
5 files changed, 374 insertions, 75 deletions
diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs index e6fb9e9d33..1cbd166323 100644 --- a/crates/parser/src/grammar/expressions.rs +++ b/crates/parser/src/grammar/expressions.rs @@ -4,8 +4,8 @@ use crate::grammar::attributes::ATTRIBUTE_FIRST; use super::*; -pub(crate) use self::atom::{block_expr, match_arm_list}; -pub(super) use self::atom::{literal, LITERAL_FIRST}; +pub(crate) use atom::{block_expr, match_arm_list}; +pub(super) use atom::{literal, LITERAL_FIRST}; #[derive(PartialEq, Eq)] pub(super) enum Semicolon { @@ -188,47 +188,56 @@ struct Restrictions { prefer_stmt: bool, } +enum Associativity { + Left, + Right, +} + /// Binding powers of operators for a Pratt parser. /// /// See <https://matklad.github.io/2020/04/13/simple-but-powerful-pratt-parsing.html> +/// +/// Note that Rust doesn't define associativity for some infix operators (e.g. `==` and `..`) and +/// requires parentheses to disambiguate. We just treat them as left associative. #[rustfmt::skip] -fn current_op(p: &Parser<'_>) -> (u8, SyntaxKind) { - const NOT_AN_OP: (u8, SyntaxKind) = (0, T![@]); +fn current_op(p: &Parser<'_>) -> (u8, SyntaxKind, Associativity) { + use Associativity::*; + const NOT_AN_OP: (u8, SyntaxKind, Associativity) = (0, T![@], Left); match p.current() { - T![|] if p.at(T![||]) => (3, T![||]), - T![|] if p.at(T![|=]) => (1, T![|=]), - T![|] => (6, T![|]), - T![>] if p.at(T![>>=]) => (1, T![>>=]), - T![>] if p.at(T![>>]) => (9, T![>>]), - T![>] if p.at(T![>=]) => (5, T![>=]), - T![>] => (5, T![>]), + T![|] if p.at(T![||]) => (3, T![||], Left), + T![|] if p.at(T![|=]) => (1, T![|=], Right), + T![|] => (6, T![|], Left), + T![>] if p.at(T![>>=]) => (1, T![>>=], Right), + T![>] if p.at(T![>>]) => (9, T![>>], Left), + T![>] if p.at(T![>=]) => (5, T![>=], Left), + T![>] => (5, T![>], Left), T![=] if p.at(T![=>]) => NOT_AN_OP, - T![=] if p.at(T![==]) => (5, T![==]), - T![=] => (1, T![=]), - T![<] if p.at(T![<=]) => (5, T![<=]), - T![<] if p.at(T![<<=]) => (1, T![<<=]), - T![<] if p.at(T![<<]) => (9, T![<<]), - T![<] => (5, T![<]), - T![+] if p.at(T![+=]) => (1, T![+=]), - T![+] => (10, T![+]), - T![^] if p.at(T![^=]) => (1, T![^=]), - T![^] => (7, T![^]), - T![%] if p.at(T![%=]) => (1, T![%=]), - T![%] => (11, T![%]), - T![&] if p.at(T![&=]) => (1, T![&=]), + T![=] if p.at(T![==]) => (5, T![==], Left), + T![=] => (1, T![=], Right), + T![<] if p.at(T![<=]) => (5, T![<=], Left), + T![<] if p.at(T![<<=]) => (1, T![<<=], Right), + T![<] if p.at(T![<<]) => (9, T![<<], Left), + T![<] => (5, T![<], Left), + T![+] if p.at(T![+=]) => (1, T![+=], Right), + T![+] => (10, T![+], Left), + T![^] if p.at(T![^=]) => (1, T![^=], Right), + T![^] => (7, T![^], Left), + T![%] if p.at(T![%=]) => (1, T![%=], Right), + T![%] => (11, T![%], Left), + T![&] if p.at(T![&=]) => (1, T![&=], Right), // If you update this, remember to update `expr_let()` too. - T![&] if p.at(T![&&]) => (4, T![&&]), - T![&] => (8, T![&]), - T![/] if p.at(T![/=]) => (1, T![/=]), - T![/] => (11, T![/]), - T![*] if p.at(T![*=]) => (1, T![*=]), - T![*] => (11, T![*]), - T![.] if p.at(T![..=]) => (2, T![..=]), - T![.] if p.at(T![..]) => (2, T![..]), - T![!] if p.at(T![!=]) => (5, T![!=]), - T![-] if p.at(T![-=]) => (1, T![-=]), - T![-] => (10, T![-]), - T![as] => (12, T![as]), + T![&] if p.at(T![&&]) => (4, T![&&], Left), + T![&] => (8, T![&], Left), + T![/] if p.at(T![/=]) => (1, T![/=], Right), + T![/] => (11, T![/], Left), + T![*] if p.at(T![*=]) => (1, T![*=], Right), + T![*] => (11, T![*], Left), + T![.] if p.at(T![..=]) => (2, T![..=], Left), + T![.] if p.at(T![..]) => (2, T![..], Left), + T![!] if p.at(T![!=]) => (5, T![!=], Left), + T![-] if p.at(T![-=]) => (1, T![-=], Right), + T![-] => (10, T![-], Left), + T![as] => (12, T![as], Left), _ => NOT_AN_OP } @@ -273,7 +282,7 @@ fn expr_bp( loop { let is_range = p.at(T![..]) || p.at(T![..=]); - let (op_bp, op) = current_op(p); + let (op_bp, op, associativity) = current_op(p); if op_bp < bp { break; } @@ -306,7 +315,11 @@ fn expr_bp( } } - expr_bp(p, None, Restrictions { prefer_stmt: false, ..r }, op_bp + 1); + let op_bp = match associativity { + Associativity::Left => op_bp + 1, + Associativity::Right => op_bp, + }; + expr_bp(p, None, Restrictions { prefer_stmt: false, ..r }, op_bp); lhs = m.complete(p, if is_range { RANGE_EXPR } else { BIN_EXPR }); } Some((lhs, BlockLike::NotBlock)) diff --git a/crates/parser/test_data/parser/ok/0028_operator_binding_power.rast b/crates/parser/test_data/parser/ok/0028_operator_binding_power.rast index ae08c0756a..4380257288 100644 --- a/crates/parser/test_data/parser/ok/0028_operator_binding_power.rast +++ b/crates/parser/test_data/parser/ok/0028_operator_binding_power.rast @@ -183,4 +183,273 @@ SOURCE_FILE COMMENT "//---&*1 - --2 * 9;" WHITESPACE "\n" R_CURLY "}" + WHITESPACE "\n\n" + FN + FN_KW "fn" + WHITESPACE " " + NAME + IDENT "right_associative" + PARAM_LIST + L_PAREN "(" + R_PAREN ")" + WHITESPACE " " + BLOCK_EXPR + STMT_LIST + L_CURLY "{" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + EQ "=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + PLUSEQ "+=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + WHITESPACE " " + MINUSEQ "-=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "d" + SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + STAREQ "*=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + WHITESPACE " " + SLASHEQ "/=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "d" + WHITESPACE " " + PERCENTEQ "%=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "e" + SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + AMPEQ "&=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + WHITESPACE " " + PIPEEQ "|=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "d" + WHITESPACE " " + CARETEQ "^=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "e" + SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + SHLEQ "<<=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + WHITESPACE " " + SHREQ ">>=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "d" + SEMICOLON ";" + WHITESPACE "\n" + R_CURLY "}" + WHITESPACE "\n\n" + FN + FN_KW "fn" + WHITESPACE " " + NAME + IDENT "mixed_associativity" + PARAM_LIST + L_PAREN "(" + R_PAREN ")" + WHITESPACE " " + BLOCK_EXPR + STMT_LIST + L_CURLY "{" + WHITESPACE "\n " + COMMENT "// (a + b) = (c += ((d * e) = f))" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + PLUS "+" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + WHITESPACE " " + EQ "=" + WHITESPACE " " + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "c" + WHITESPACE " " + PLUSEQ "+=" + WHITESPACE " " + BIN_EXPR + BIN_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "d" + WHITESPACE " " + STAR "*" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "e" + WHITESPACE " " + EQ "=" + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "f" + SEMICOLON ";" + WHITESPACE "\n" + R_CURLY "}" WHITESPACE "\n" diff --git a/crates/parser/test_data/parser/ok/0028_operator_binding_power.rs b/crates/parser/test_data/parser/ok/0028_operator_binding_power.rs index cc9598470d..7ee3013a0c 100644 --- a/crates/parser/test_data/parser/ok/0028_operator_binding_power.rs +++ b/crates/parser/test_data/parser/ok/0028_operator_binding_power.rs @@ -12,3 +12,16 @@ fn binding_power() { //1 = 2 .. 3; //---&*1 - --2 * 9; } + +fn right_associative() { + a = b = c; + a = b += c -= d; + a = b *= c /= d %= e; + a = b &= c |= d ^= e; + a = b <<= c >>= d; +} + +fn mixed_associativity() { + // (a + b) = (c += ((d * e) = f)) + a + b = c += d * e = f; +} diff --git a/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rast b/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rast index e8b836dfbd..ce75c55189 100644 --- a/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rast +++ b/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rast @@ -168,42 +168,46 @@ SOURCE_FILE WHITESPACE "\n " EXPR_STMT BIN_EXPR - BIN_EXPR - CALL_EXPR - PATH_EXPR - PATH - PATH_SEGMENT - NAME_REF - IDENT "Some" - ARG_LIST - L_PAREN "(" - RANGE_EXPR - DOT2 ".." - R_PAREN ")" - WHITESPACE " " - EQ "=" - WHITESPACE " " - METHOD_CALL_EXPR - CALL_EXPR - PATH_EXPR - PATH - PATH_SEGMENT - NAME_REF - IDENT "Some" - ARG_LIST - L_PAREN "(" - LITERAL - INT_NUMBER "0" - R_PAREN ")" - DOT "." - WHITESPACE "\n " - NAME_REF - IDENT "Ok" - ARG_LIST - L_PAREN "(" - UNDERSCORE_EXPR - UNDERSCORE "_" - R_PAREN ")" + CALL_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "Some" + ARG_LIST + L_PAREN "(" + RANGE_EXPR + DOT2 ".." + R_PAREN ")" + WHITESPACE " " + EQ "=" + WHITESPACE " " + CALL_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "Some" + ARG_LIST + L_PAREN "(" + LITERAL + INT_NUMBER "0" + R_PAREN ")" + SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + BIN_EXPR + CALL_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "Ok" + ARG_LIST + L_PAREN "(" + UNDERSCORE_EXPR + UNDERSCORE "_" + R_PAREN ")" WHITESPACE " " EQ "=" WHITESPACE " " diff --git a/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rs b/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rs index 9d3e86603f..d223b11f23 100644 --- a/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rs +++ b/crates/parser/test_data/parser/ok/0072_destructuring_assignment.rs @@ -4,7 +4,7 @@ fn foo() { (_) = ..; struct S { a: i32 } S { .. } = S { ..S::default() }; - Some(..) = Some(0). + Some(..) = Some(0); Ok(_) = 0; let (a, b); [a, .., b] = [1, .., 2]; |