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cleanup dollar handling in expressions

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This commit is contained in:
Aleksey Kladov 2019-09-10 21:28:27 +03:00
parent 1140a83c1b
commit b9d9db83d1
3 changed files with 51 additions and 96 deletions
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49
crates/ra_parser/src/grammar/expressions.rs
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@ -14,20 +14,17 @@ const EXPR_FIRST: TokenSet = LHS_FIRST;
pub(super) fn expr(p: &mut Parser) -> BlockLike {
let r = Restrictions { forbid_structs: false, prefer_stmt: false };
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl).1
expr_bp(p, r, 1).1
}
pub(super) fn expr_stmt(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
let r = Restrictions { forbid_structs: false, prefer_stmt: true };
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl)
expr_bp(p, r, 1)
}
fn expr_no_struct(p: &mut Parser) {
let r = Restrictions { forbid_structs: true, prefer_stmt: false };
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl);
expr_bp(p, r, 1);
}
// test block
@ -257,23 +254,8 @@ fn current_op(p: &Parser) -> (u8, SyntaxKind) {
}
// Parses expression with binding power of at least bp.
fn expr_bp(
p: &mut Parser,
r: Restrictions,
mut bp: u8,
dollar_lvl: &mut usize,
) -> (Option<CompletedMarker>, BlockLike) {
// `newly_dollar_open` is a flag indicated that dollar is just closed after lhs, e.g.
// `$1$ + a`
// We use this flag to skip handling it.
let mut newly_dollar_open = if p.at_l_dollar() {
*dollar_lvl += p.eat_l_dollars();
true
} else {
false
};
let mut lhs = match lhs(p, r, dollar_lvl) {
fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> (Option<CompletedMarker>, BlockLike) {
let mut lhs = match lhs(p, r) {
Some((lhs, blocklike)) => {
// test stmt_bin_expr_ambiguity
// fn foo() {
@ -289,15 +271,6 @@ fn expr_bp(
};
loop {
if *dollar_lvl > 0 && p.at_r_dollar() {
*dollar_lvl -= p.eat_r_dollars(*dollar_lvl);
if !newly_dollar_open {
// We "pump" bp for make it highest priority
bp = 255;
}
newly_dollar_open = false;
}
let is_range = p.at(T![..]) || p.at(T![..=]);
let (op_bp, op) = current_op(p);
if op_bp < bp {
@ -306,7 +279,7 @@ fn expr_bp(
let m = lhs.precede(p);
p.bump(op);
expr_bp(p, r, op_bp + 1, dollar_lvl);
expr_bp(p, r, op_bp + 1);
lhs = m.complete(p, if is_range { RANGE_EXPR } else { BIN_EXPR });
}
(Some(lhs), BlockLike::NotBlock)
@ -314,11 +287,7 @@ fn expr_bp(
const LHS_FIRST: TokenSet = atom::ATOM_EXPR_FIRST.union(token_set![AMP, STAR, EXCL, DOT, MINUS]);
fn lhs(
p: &mut Parser,
r: Restrictions,
dollar_lvl: &mut usize,
) -> Option<(CompletedMarker, BlockLike)> {
fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
let m;
let kind = match p.current() {
// test ref_expr
@ -351,7 +320,7 @@ fn lhs(
m = p.start();
p.bump(op);
if p.at_ts(EXPR_FIRST) {
expr_bp(p, r, 2, dollar_lvl);
expr_bp(p, r, 2);
}
return Some((m.complete(p, RANGE_EXPR), BlockLike::NotBlock));
}
@ -367,7 +336,7 @@ fn lhs(
return Some(postfix_expr(p, lhs, blocklike, !(r.prefer_stmt && blocklike.is_block())));
}
};
expr_bp(p, r, 255, dollar_lvl);
expr_bp(p, r, 255);
Some((m.complete(p, kind), BlockLike::NotBlock))
}