//! FIXME: write short doc here use super::*; // test expr_literals // fn foo() { // let _ = true; // let _ = false; // let _ = 1; // let _ = 2.0; // let _ = b'a'; // let _ = 'b'; // let _ = "c"; // let _ = r"d"; // let _ = b"e"; // let _ = br"f"; // } pub(crate) const LITERAL_FIRST: TokenSet = token_set![ TRUE_KW, FALSE_KW, INT_NUMBER, FLOAT_NUMBER, BYTE, CHAR, STRING, RAW_STRING, BYTE_STRING, RAW_BYTE_STRING ]; pub(crate) fn literal(p: &mut Parser) -> Option<CompletedMarker> { if !p.at_ts(LITERAL_FIRST) { return None; } let m = p.start(); p.bump_any(); Some(m.complete(p, LITERAL)) } // E.g. for after the break in `if break {}`, this should not match pub(super) const ATOM_EXPR_FIRST: TokenSet = LITERAL_FIRST.union(paths::PATH_FIRST).union(token_set![ T!['('], T!['{'], T!['['], L_DOLLAR, T![|], T![move], T![box], T![if], T![while], T![match], T![unsafe], T![return], T![break], T![continue], T![async], T![try], T![loop], T![for], LIFETIME, ]); const EXPR_RECOVERY_SET: TokenSet = token_set![LET_KW]; pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> { if let Some(m) = literal(p) { return Some((m, BlockLike::NotBlock)); } if paths::is_path_start(p) { return Some(path_expr(p, r)); } let la = p.nth(1); let done = match p.current() { T!['('] => tuple_expr(p), T!['['] => array_expr(p), L_DOLLAR => meta_var_expr(p), T![|] => lambda_expr(p), T![move] if la == T![|] => lambda_expr(p), T![async] if la == T![|] || (la == T![move] && p.nth(2) == T![|]) => lambda_expr(p), T![if] => if_expr(p), T![loop] => loop_expr(p, None), T![box] => box_expr(p, None), T![for] => for_expr(p, None), T![while] => while_expr(p, None), T![try] => try_block_expr(p, None), LIFETIME if la == T![:] => { let m = p.start(); label(p); match p.current() { T![loop] => loop_expr(p, Some(m)), T![for] => for_expr(p, Some(m)), T![while] => while_expr(p, Some(m)), T!['{'] => block_expr(p, Some(m)), _ => { // test_err misplaced_label_err // fn main() { // 'loop: impl // } p.error("expected a loop"); m.complete(p, ERROR); return None; } } } T![async] if la == T!['{'] || (la == T![move] && p.nth(2) == T!['{']) => { let m = p.start(); p.bump(T![async]); p.eat(T![move]); block_expr(p, Some(m)) } T![match] => match_expr(p), T![unsafe] if la == T!['{'] => { let m = p.start(); p.bump(T![unsafe]); block_expr(p, Some(m)) } T!['{'] => { // test for_range_from // fn foo() { // for x in 0 .. { // break; // } // } block_expr(p, None) } T![return] => return_expr(p), T![continue] => continue_expr(p), T![break] => break_expr(p, r), _ => { p.err_recover("expected expression", EXPR_RECOVERY_SET); return None; } }; let blocklike = match done.kind() { IF_EXPR | WHILE_EXPR | FOR_EXPR | LOOP_EXPR | MATCH_EXPR | BLOCK_EXPR | TRY_BLOCK_EXPR => { BlockLike::Block } _ => BlockLike::NotBlock, }; Some((done, blocklike)) } // test tuple_expr // fn foo() { // (); // (1); // (1,); // } fn tuple_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T!['('])); let m = p.start(); p.expect(T!['(']); let mut saw_comma = false; let mut saw_expr = false; while !p.at(EOF) && !p.at(T![')']) { saw_expr = true; if !p.at_ts(EXPR_FIRST) { p.error("expected expression"); break; } expr(p); if !p.at(T![')']) { saw_comma = true; p.expect(T![,]); } } p.expect(T![')']); m.complete(p, if saw_expr && !saw_comma { PAREN_EXPR } else { TUPLE_EXPR }) } // test array_expr // fn foo() { // []; // [1]; // [1, 2,]; // [1; 2]; // } fn array_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T!['['])); let m = p.start(); p.bump(T!['[']); if p.eat(T![']']) { return m.complete(p, ARRAY_EXPR); } // test first_array_member_attributes // pub const A: &[i64] = &[ // #[cfg(test)] // 1, // 2, // ]; attributes::outer_attributes(p); expr(p); if p.eat(T![;]) { expr(p); p.expect(T![']']); return m.complete(p, ARRAY_EXPR); } while !p.at(EOF) && !p.at(T![']']) { p.expect(T![,]); if p.at(T![']']) { break; } // test subsequent_array_member_attributes // pub const A: &[i64] = &[ // 1, // #[cfg(test)] // 2, // ]; attributes::outer_attributes(p); if !p.at_ts(EXPR_FIRST) { p.error("expected expression"); break; } expr(p); } p.expect(T![']']); m.complete(p, ARRAY_EXPR) } // test lambda_expr // fn foo() { // || (); // || -> i32 { 92 }; // |x| x; // move |x: i32,| x; // async || {}; // move || {}; // async move || {}; // } fn lambda_expr(p: &mut Parser) -> CompletedMarker { assert!( p.at(T![|]) || (p.at(T![move]) && p.nth(1) == T![|]) || (p.at(T![async]) && p.nth(1) == T![|]) || (p.at(T![async]) && p.nth(1) == T![move] && p.nth(2) == T![|]) ); let m = p.start(); p.eat(T![async]); p.eat(T![move]); params::param_list_opt_types(p); if opt_fn_ret_type(p) { if !p.at(T!['{']) { p.error("expected `{`"); } } if p.at_ts(EXPR_FIRST) { expr(p); } else { p.error("expected expression"); } m.complete(p, LAMBDA_EXPR) } // test if_expr // fn foo() { // if true {}; // if true {} else {}; // if true {} else if false {} else {}; // if S {}; // if { true } { } else { }; // } fn if_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![if])); let m = p.start(); p.bump(T![if]); cond(p); block(p); if p.at(T![else]) { p.bump(T![else]); if p.at(T![if]) { if_expr(p); } else { block(p); } } m.complete(p, IF_EXPR) } // test label // fn foo() { // 'a: loop {} // 'b: while true {} // 'c: for x in () {} // } fn label(p: &mut Parser) { assert!(p.at(LIFETIME) && p.nth(1) == T![:]); let m = p.start(); p.bump(LIFETIME); p.bump_any(); m.complete(p, LABEL); } // test loop_expr // fn foo() { // loop {}; // } fn loop_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T![loop])); let m = m.unwrap_or_else(|| p.start()); p.bump(T![loop]); block(p); m.complete(p, LOOP_EXPR) } // test while_expr // fn foo() { // while true {}; // while let Some(x) = it.next() {}; // while { true } {}; // } fn while_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T![while])); let m = m.unwrap_or_else(|| p.start()); p.bump(T![while]); cond(p); block(p); m.complete(p, WHILE_EXPR) } // test for_expr // fn foo() { // for x in [] {}; // } fn for_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T![for])); let m = m.unwrap_or_else(|| p.start()); p.bump(T![for]); patterns::pattern(p); p.expect(T![in]); expr_no_struct(p); block(p); m.complete(p, FOR_EXPR) } // test cond // fn foo() { if let Some(_) = None {} } // fn bar() { // if let Some(_) | Some(_) = None {} // if let | Some(_) = None {} // while let Some(_) | Some(_) = None {} // while let | Some(_) = None {} // } fn cond(p: &mut Parser) { let m = p.start(); if p.eat(T![let]) { patterns::pattern_list(p); p.expect(T![=]); } expr_no_struct(p); m.complete(p, CONDITION); } // test match_expr // fn foo() { // match () { }; // match S {}; // match { } { _ => () }; // match { S {} } {}; // } fn match_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![match])); let m = p.start(); p.bump(T![match]); expr_no_struct(p); if p.at(T!['{']) { match_arm_list(p); } else { p.error("expected `{`") } m.complete(p, MATCH_EXPR) } pub(crate) fn match_arm_list(p: &mut Parser) { assert!(p.at(T!['{'])); let m = p.start(); p.eat(T!['{']); // test match_arms_inner_attribute // fn foo() { // match () { // #![doc("Inner attribute")] // #![doc("Can be")] // #![doc("Stacked")] // _ => (), // } // } attributes::inner_attributes(p); while !p.at(EOF) && !p.at(T!['}']) { if p.at(T!['{']) { error_block(p, "expected match arm"); continue; } // test match_arms_commas // fn foo() { // match () { // _ => (), // _ => {} // _ => () // } // } if match_arm(p).is_block() { p.eat(T![,]); } else if !p.at(T!['}']) { p.expect(T![,]); } } p.expect(T!['}']); m.complete(p, MATCH_ARM_LIST); } // test match_arm // fn foo() { // match () { // _ => (), // _ if Test > Test{field: 0} => (), // X | Y if Z => (), // | X | Y if Z => (), // | X => (), // }; // } fn match_arm(p: &mut Parser) -> BlockLike { let m = p.start(); // test match_arms_outer_attributes // fn foo() { // match () { // #[cfg(feature = "some")] // _ => (), // #[cfg(feature = "other")] // _ => (), // #[cfg(feature = "many")] // #[cfg(feature = "attributes")] // #[cfg(feature = "before")] // _ => (), // } // } attributes::outer_attributes(p); patterns::pattern_list_r(p, TokenSet::EMPTY); if p.at(T![if]) { match_guard(p); } p.expect(T![=>]); let blocklike = expr_stmt(p).1; m.complete(p, MATCH_ARM); blocklike } // test match_guard // fn foo() { // match () { // _ if foo => (), // } // } fn match_guard(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![if])); let m = p.start(); p.bump(T![if]); expr(p); m.complete(p, MATCH_GUARD) } // test block_expr // fn foo() { // {}; // unsafe {}; // 'label: {}; // } pub(super) fn block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T!['{'])); let m = m.unwrap_or_else(|| p.start()); naked_block(p); m.complete(p, BLOCK_EXPR) } // test return_expr // fn foo() { // return; // return 92; // } fn return_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![return])); let m = p.start(); p.bump(T![return]); if p.at_ts(EXPR_FIRST) { expr(p); } m.complete(p, RETURN_EXPR) } // test continue_expr // fn foo() { // loop { // continue; // continue 'l; // } // } fn continue_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(T![continue])); let m = p.start(); p.bump(T![continue]); p.eat(LIFETIME); m.complete(p, CONTINUE_EXPR) } // test break_expr // fn foo() { // loop { // break; // break 'l; // break 92; // break 'l 92; // } // } fn break_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker { assert!(p.at(T![break])); let m = p.start(); p.bump(T![break]); p.eat(LIFETIME); // test break_ambiguity // fn foo(){ // if break {} // while break {} // for i in break {} // match break {} // } if p.at_ts(EXPR_FIRST) && !(r.forbid_structs && p.at(T!['{'])) { expr(p); } m.complete(p, BREAK_EXPR) } // test try_block_expr // fn foo() { // let _ = try {}; // } fn try_block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T![try])); let m = m.unwrap_or_else(|| p.start()); p.bump(T![try]); block(p); m.complete(p, TRY_EXPR) } // test box_expr // fn foo() { // let x = box 1i32; // let y = (box 1i32, box 2i32); // let z = Foo(box 1i32, box 2i32); // } fn box_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker { assert!(p.at(T![box])); let m = m.unwrap_or_else(|| p.start()); p.bump(T![box]); if p.at_ts(EXPR_FIRST) { expr(p); } m.complete(p, BOX_EXPR) } /// Expression from `$var` macro expansion, wrapped in dollars fn meta_var_expr(p: &mut Parser) -> CompletedMarker { assert!(p.at(L_DOLLAR)); let m = p.start(); p.bump(L_DOLLAR); let (completed, _is_block) = expr_bp(p, Restrictions { forbid_structs: false, prefer_stmt: false }, 1); match (completed, p.current()) { (Some(it), R_DOLLAR) => { p.bump(R_DOLLAR); m.abandon(p); it } _ => { while !p.at(R_DOLLAR) { p.bump_any() } p.bump(R_DOLLAR); m.complete(p, ERROR) } } }