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Remove extra level of nesting.

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This commit is contained in:
Mark-Simulacrum 2016-11-12 07:41:47 -07:00
parent 38912ee3d4
commit 2189f573ca
1 changed files with 32 additions and 35 deletions
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67
src/libsyntax/ext/tt/macro_parser.rs
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@ -436,43 +436,40 @@ pub fn parse(sess: &ParseSess, rdr: TtReader, ms: &[TokenTree]) -> NamedParseRes
} else { } else {
return Failure(parser.span, token::Eof); return Failure(parser.span, token::Eof);
} }
} else { } else if (!bb_eis.is_empty() && !next_eis.is_empty()) || bb_eis.len() > 1 {
if (!bb_eis.is_empty() && !next_eis.is_empty()) let nts = bb_eis.iter().map(|ei| match ei.top_elts.get_tt(ei.idx) {
|| bb_eis.len() > 1 { TokenTree::Token(_, MatchNt(bind, name)) => {
let nts = bb_eis.iter().map(|ei| match ei.top_elts.get_tt(ei.idx) { format!("{} ('{}')", name, bind)
TokenTree::Token(_, MatchNt(bind, name)) => {
format!("{} ('{}')", name, bind)
}
_ => panic!()
}).collect::<Vec<String>>().join(" or ");
return Error(parser.span, format!(
"local ambiguity: multiple parsing options: {}",
match next_eis.len() {
0 => format!("built-in NTs {}.", nts),
1 => format!("built-in NTs {} or 1 other option.", nts),
n => format!("built-in NTs {} or {} other options.", nts, n),
}
))
} else if bb_eis.is_empty() && next_eis.is_empty() {
return Failure(parser.span, parser.token);
} else if !next_eis.is_empty() {
/* Now process the next token */
cur_eis.extend(next_eis.drain(..));
parser.bump();
} else /* bb_eis.len() == 1 */ {
let mut ei = bb_eis.pop().unwrap();
if let TokenTree::Token(span, MatchNt(_, ident)) = ei.top_elts.get_tt(ei.idx) {
let match_cur = ei.match_cur;
ei.matches[match_cur].push(Rc::new(MatchedNonterminal(
Rc::new(parse_nt(&mut parser, span, &ident.name.as_str())))));
ei.idx += 1;
ei.match_cur += 1;
} else {
unreachable!()
} }
cur_eis.push(ei); _ => panic!()
}).collect::<Vec<String>>().join(" or ");
return Error(parser.span, format!(
"local ambiguity: multiple parsing options: {}",
match next_eis.len() {
0 => format!("built-in NTs {}.", nts),
1 => format!("built-in NTs {} or 1 other option.", nts),
n => format!("built-in NTs {} or {} other options.", nts, n),
}
));
} else if bb_eis.is_empty() && next_eis.is_empty() {
return Failure(parser.span, parser.token);
} else if !next_eis.is_empty() {
/* Now process the next token */
cur_eis.extend(next_eis.drain(..));
parser.bump();
} else /* bb_eis.len() == 1 */ {
let mut ei = bb_eis.pop().unwrap();
if let TokenTree::Token(span, MatchNt(_, ident)) = ei.top_elts.get_tt(ei.idx) {
let match_cur = ei.match_cur;
ei.matches[match_cur].push(Rc::new(MatchedNonterminal(
Rc::new(parse_nt(&mut parser, span, &ident.name.as_str())))));
ei.idx += 1;
ei.match_cur += 1;
} else {
unreachable!()
} }
cur_eis.push(ei);
} }
assert!(!cur_eis.is_empty()); assert!(!cur_eis.is_empty());