Fix bug and add expr , pat , ty matcher

This commit is contained in:
Edwin Cheng 2019-04-13 18:38:31 +08:00
parent f66300ccd1
commit 6646d49f23
10 changed files with 307 additions and 33 deletions

View file

@ -8,17 +8,20 @@ const EXPR_FIRST: TokenSet = LHS_FIRST;
pub(super) fn expr(p: &mut Parser) -> BlockLike {
let r = Restrictions { forbid_structs: false, prefer_stmt: false };
expr_bp(p, r, 1).1
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl).1
}
pub(super) fn expr_stmt(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
let r = Restrictions { forbid_structs: false, prefer_stmt: true };
expr_bp(p, r, 1)
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl)
}
fn expr_no_struct(p: &mut Parser) {
let r = Restrictions { forbid_structs: true, prefer_stmt: false };
expr_bp(p, r, 1);
let mut dollar_lvl = 0;
expr_bp(p, r, 1, &mut dollar_lvl);
}
// test block
@ -206,8 +209,23 @@ fn current_op(p: &Parser) -> (u8, Op) {
}
// Parses expression with binding power of at least bp.
fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> (Option<CompletedMarker>, BlockLike) {
let mut lhs = match lhs(p, r) {
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 = false;
if p.at_l_dollar() {
*dollar_lvl += p.eat_l_dollars();
newly_dollar_open = true;
}
let mut lhs = match lhs(p, r, dollar_lvl) {
Some((lhs, blocklike)) => {
// test stmt_bin_expr_ambiguity
// fn foo() {
@ -223,6 +241,15 @@ fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> (Option<CompletedMarker>,
};
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.current() == DOTDOT || p.current() == DOTDOTEQ;
let (op_bp, op) = current_op(p);
if op_bp < bp {
@ -235,7 +262,8 @@ fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> (Option<CompletedMarker>,
p.bump_compound(kind, n);
}
}
expr_bp(p, r, op_bp + 1);
expr_bp(p, r, op_bp + 1, dollar_lvl);
lhs = m.complete(p, if is_range { RANGE_EXPR } else { BIN_EXPR });
}
(Some(lhs), BlockLike::NotBlock)
@ -244,7 +272,11 @@ fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> (Option<CompletedMarker>,
const LHS_FIRST: TokenSet =
atom::ATOM_EXPR_FIRST.union(token_set![AMP, STAR, EXCL, DOTDOT, DOTDOTEQ, MINUS]);
fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
fn lhs(
p: &mut Parser,
r: Restrictions,
dollar_lvl: &mut usize,
) -> Option<(CompletedMarker, BlockLike)> {
let m;
let kind = match p.current() {
// test ref_expr
@ -275,7 +307,7 @@ fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)>
m = p.start();
p.bump();
if p.at_ts(EXPR_FIRST) {
expr_bp(p, r, 2);
expr_bp(p, r, 2, dollar_lvl);
}
return Some((m.complete(p, RANGE_EXPR), BlockLike::NotBlock));
}
@ -287,7 +319,7 @@ fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)>
));
}
};
expr_bp(p, r, 255);
expr_bp(p, r, 255, dollar_lvl);
Some((m.complete(p, kind), BlockLike::NotBlock))
}