bjoernager/rust
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auto merge of #5002 : catamorphism/rust/one-tuples, r=graydon

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r? @graydon - This is for greater uniformity (for example, macros that generate
tuples). rustc already supported 1-tuple patterns, but there was no
way to construct a 1-tuple term.

@graydon , as far as your comment on #4898 - it did turn out to be solvable inside the macro (since @luqmana already fixed it using structs instead), but I still think it's a good idea to allow 1-tuples, for uniformity. I don't think anyone is likely to trip over it, and I'm not too worried that it changes the amount of ambiguity.
This commit is contained in:
bors 2013-02-19 09:14:33 -08:00
commit f68335113b
6 changed files with 69 additions and 11 deletions
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36
src/libsyntax/parse/parser.rs
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@ -576,12 +576,21 @@ pub impl Parser {
self.bump();
ty_nil
} else {
// (t) is a parenthesized ty
// (t,) is the type of a tuple with only one field,
// of type t
let mut ts = ~[self.parse_ty(false)];
let mut one_tuple = false;
while self.token == token::COMMA {
self.bump();
ts.push(self.parse_ty(false));
if self.token != token::RPAREN {
ts.push(self.parse_ty(false));
}
else {
one_tuple = true;
}
}
let t = if vec::len(ts) == 1u { ts[0].node }
let t = if ts.len() == 1 && !one_tuple { ts[0].node }
else { ty_tup(ts) };
self.expect(token::RPAREN);
t
@ -1061,6 +1070,9 @@ pub impl Parser {
if self.token == token::LPAREN {
self.bump();
// (e) is parenthesized e
// (e,) is a tuple with only one field, e
let mut one_tuple = false;
if self.token == token::RPAREN {
hi = self.span.hi;
self.bump();
@ -1069,12 +1081,18 @@ pub impl Parser {
}
let mut es = ~[self.parse_expr()];
while self.token == token::COMMA {
self.bump(); es.push(self.parse_expr());
self.bump();
if self.token != token::RPAREN {
es.push(self.parse_expr());
}
else {
one_tuple = true;
}
}
hi = self.span.hi;
self.expect(token::RPAREN);
return if es.len() == 1 {
return if es.len() == 1 && !one_tuple {
self.mk_expr(lo, self.span.hi, expr_paren(es[0]))
}
else {
@ -2158,11 +2176,13 @@ pub impl Parser {
pat = pat_lit(expr);
} else {
let mut fields = ~[self.parse_pat(refutable)];
while self.token == token::COMMA {
self.bump();
fields.push(self.parse_pat(refutable));
if self.look_ahead(1) != token::RPAREN {
while self.token == token::COMMA {
self.bump();
fields.push(self.parse_pat(refutable));
}
}
if vec::len(fields) == 1u { self.expect(token::COMMA); }
if fields.len() == 1 { self.expect(token::COMMA); }
hi = self.span.hi;
self.expect(token::RPAREN);
pat = pat_tup(fields);