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Attempted fix for ? kleene op

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This commit is contained in:
Mark Mansi 2018-01-25 12:45:27 -06:00
parent 5ac48ec826
commit f59b821944
1 changed files with 21 additions and 23 deletions
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44
src/libsyntax/ext/tt/macro_parser.rs
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@ -181,6 +181,8 @@ struct MatcherPos {
match_hi: usize,
// Specifically used if we are matching a repetition. If we aren't both should be `None`.
/// The KleeneOp of this sequence if we are in a repetition.
seq_op: Option<quoted::KleeneOp>,
/// The separator if we are in a repetition
sep: Option<Token>,
/// The "parent" matcher position if we are in a repetition. That is, the matcher position just
@ -263,6 +265,7 @@ fn initial_matcher_pos(ms: Vec<TokenTree>, lo: BytePos) -> Box<MatcherPos> {
stack: vec![],
// Haven't descended into any sequences, so both of these are `None`.
seq_op: None,
sep: None,
up: None,
})
@ -464,10 +467,11 @@ fn inner_parse_loop(
item.idx += 1;
next_items.push(item);
}
}
}
// We don't need a separator. Move the "dot" back to the beginning of the matcher
// and try to match again.
else {
// and try to match again UNLESS we are only allowed to have _one_ repetition.
else if item.seq_op != Some(quoted::KleeneOp::ZeroOrOne) {
// we don't need a separator
item.match_cur = item.match_lo;
item.idx = 0;
cur_items.push(item);
@ -499,26 +503,20 @@ fn inner_parse_loop(
cur_items.push(new_item);
}
// For ZeroOrMore and OneOrMore, we want to examine the case were there is at
// least one match. For ZeroOrOne, we only want the case where there is exactly
// one match.
if (seq.op == quoted::KleeneOp::ZeroOrOne && seq.num_captures == 1)
|| seq.op != quoted::KleeneOp::ZeroOrOne
{
let matches = create_matches(item.matches.len());
cur_items.push(Box::new(MatcherPos {
stack: vec![],
sep: seq.separator.clone(),
idx: 0,
matches,
match_lo: item.match_cur,
match_cur: item.match_cur,
match_hi: item.match_cur + seq.num_captures,
up: Some(item),
sp_lo: sp.lo(),
top_elts: Tt(TokenTree::Sequence(sp, seq)),
}));
}
let matches = create_matches(item.matches.len());
cur_items.push(Box::new(MatcherPos {
stack: vec![],
sep: seq.separator.clone(),
seq_op: Some(seq.op),
idx: 0,
matches,
match_lo: item.match_cur,
match_cur: item.match_cur,
match_hi: item.match_cur + seq.num_captures,
up: Some(item),
sp_lo: sp.lo(),
top_elts: Tt(TokenTree::Sequence(sp, seq)),
}));
}
// We need to match a metavar (but the identifier is invalid)... this is an error