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rustc: Allow trailing comma in record fields #1207

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76 changes: 48 additions & 28 deletions src/comp/syntax/parse/parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -290,7 +290,7 @@ fn parse_ty_fn(proto: ast::proto, p: parser) -> ast::ty_ {
ret spanned(lo, t.span.hi, {mode: mode, ty: t});
}
let inputs =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_fn_input_ty, p);
// FIXME: there's no syntax for this right now anyway
// auto constrs = parse_constrs(~[], p);
Expand Down Expand Up @@ -319,7 +319,8 @@ fn parse_ty_obj(p: parser) -> ast::ty_ {
}
}
let meths =
parse_seq(token::LBRACE, token::RBRACE, none, parse_method_sig, p);
parse_seq(token::LBRACE, token::RBRACE, seq_sep_none(),
parse_method_sig, p);
ret ast::ty_obj(meths.node);
}

Expand Down Expand Up @@ -376,7 +377,7 @@ fn parse_ty_constr(fn_args: [ast::arg], p: parser) -> @ast::constr {
let lo = p.get_lo_pos();
let path = parse_path(p);
let args: {node: [@ast::constr_arg], span: span} =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
{|p| parse_constr_arg(fn_args, p)}, p);
ret @spanned(lo, args.span.hi,
{path: path, args: args.node, id: p.get_id()});
Expand All @@ -386,7 +387,7 @@ fn parse_constr_in_type(p: parser) -> @ast::ty_constr {
let lo = p.get_lo_pos();
let path = parse_path(p);
let args: [@ast::ty_constr_arg] =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_type_constr_arg, p).node;
let hi = p.get_lo_pos();
let tc: ast::ty_constr_ = {path: path, args: args, id: p.get_id()};
Expand Down Expand Up @@ -540,7 +541,7 @@ fn parse_ty(p: parser, colons_before_params: bool) -> @ast::ty {
t = ast::ty_ptr(parse_mt(p));
} else if p.peek() == token::LBRACE {
let elems =
parse_seq(token::LBRACE, token::RBRACE, some(token::COMMA),
parse_seq(token::LBRACE, token::RBRACE, seq_sep_opt(token::COMMA),
parse_ty_field, p);
let hi = elems.span.hi;
t = ast::ty_rec(elems.node);
Expand Down Expand Up @@ -631,31 +632,47 @@ fn parse_seq_lt_gt<copy T>(sep: option::t<token::token>,
ret spanned(lo, hi, result);
}

fn parse_seq_to_end<copy T>(ket: token::token, sep: option::t<token::token>,
fn parse_seq_to_end<copy T>(ket: token::token, sep: seq_sep,
f: block(parser) -> T, p: parser) -> [T] {
let val = parse_seq_to_before_end(ket, sep, f, p);
p.bump();
ret val;
}

type seq_sep = {
sep: option::t<token::token>,
trailing_opt: bool // is trailing separator optional?
};

fn seq_sep(t: token::token) -> seq_sep {
ret {sep: option::some(t), trailing_opt: false};
}
fn seq_sep_opt(t: token::token) -> seq_sep {
ret {sep: option::some(t), trailing_opt: true};
}
fn seq_sep_none() -> seq_sep {
ret {sep: option::none, trailing_opt: false};
}

fn parse_seq_to_before_end<copy T>(ket: token::token,
sep: option::t<token::token>,
sep: seq_sep,
f: block(parser) -> T, p: parser) -> [T] {
let first: bool = true;
let v: [T] = [];
while p.peek() != ket {
alt sep {
alt sep.sep {
some(t) { if first { first = false; } else { expect(p, t); } }
_ { }
}
if sep.trailing_opt && p.peek() == ket { break; }
v += [f(p)];
}
ret v;
}


fn parse_seq<copy T>(bra: token::token, ket: token::token,
sep: option::t<token::token>, f: block(parser) -> T,
sep: seq_sep, f: block(parser) -> T,
p: parser) -> spanned<[T]> {
let lo = p.get_lo_pos();
expect(p, bra);
Expand Down Expand Up @@ -810,6 +827,10 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
while p.peek() != token::RBRACE {
if eat_word(p, "with") { base = some(parse_expr(p)); break; }
expect(p, token::COMMA);
if p.peek() == token::RBRACE {
// record ends by an optional trailing comma
break;
}
fields += [parse_field(p, token::COLON)];
}
hi = p.get_hi_pos();
Expand Down Expand Up @@ -850,8 +871,8 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
p.bump();
let mut = parse_mutability(p);
let es =
parse_seq_to_end(token::RBRACKET, some(token::COMMA), parse_expr,
p);
parse_seq_to_end(token::RBRACKET, seq_sep(token::COMMA),
parse_expr, p);
ex = ast::expr_vec(es, mut);
} else if p.peek() == token::POUND_LT {
p.bump();
Expand All @@ -876,7 +897,7 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
if p.peek() == token::LPAREN {
p.bump();
fields =
some(parse_seq_to_end(token::RPAREN, some(token::COMMA),
some(parse_seq_to_end(token::RPAREN, seq_sep(token::COMMA),
parse_anon_obj_field, p));
}
let meths: [@ast::method] = [];
Expand Down Expand Up @@ -906,7 +927,7 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
}
}
let es =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_expr_opt, p);
hi = es.span.hi;
ex = ast::expr_bind(e, es.node);
Expand Down Expand Up @@ -977,7 +998,7 @@ fn parse_bottom_expr(p: parser) -> @ast::expr {
// The rest is a call expression.
let f: @ast::expr = parse_self_method(p);
let es =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_expr, p);
hi = es.span.hi;
ex = ast::expr_call(f, es.node, false);
Expand Down Expand Up @@ -1016,13 +1037,12 @@ fn parse_syntax_ext_naked(p: parser, lo: uint) -> @ast::expr {
p.fatal("expected a syntax expander name");
}
//temporary for a backwards-compatible cycle:
let sep = seq_sep(token::COMMA);
let es =
if p.peek() == token::LPAREN {
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_expr, p)
parse_seq(token::LPAREN, token::RPAREN, sep, parse_expr, p)
} else {
parse_seq(token::LBRACKET, token::RBRACKET, some(token::COMMA),
parse_expr, p)
parse_seq(token::LBRACKET, token::RBRACKET, sep, parse_expr, p)
};
let hi = es.span.hi;
let e = mk_expr(p, es.span.lo, hi, ast::expr_vec(es.node, ast::imm));
Expand Down Expand Up @@ -1053,7 +1073,7 @@ fn parse_dot_or_call_expr_with(p: parser, e: @ast::expr) -> @ast::expr {
} else {
// Call expr.
let es = parse_seq(token::LPAREN, token::RPAREN,
some(token::COMMA), parse_expr, p);
seq_sep(token::COMMA), parse_expr, p);
hi = es.span.hi;
let nd = ast::expr_call(e, es.node, false);
e = mk_expr(p, lo, hi, nd);
Expand Down Expand Up @@ -1508,7 +1528,7 @@ fn parse_pat(p: parser) -> @ast::pat {
token::LPAREN. {
let a =
parse_seq(token::LPAREN, token::RPAREN,
some(token::COMMA), parse_pat, p);
seq_sep(token::COMMA), parse_pat, p);
args = a.node;
hi = a.span.hi;
}
Expand Down Expand Up @@ -1761,8 +1781,8 @@ fn parse_ty_params(p: parser) -> [ast::ty_param] {
fn parse_fn_decl(p: parser, purity: ast::purity, il: ast::inlineness) ->
ast::fn_decl {
let inputs: ast::spanned<[ast::arg]> =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA), parse_arg,
p);
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_arg, p);
// Use the args list to translate each bound variable
// mentioned in a constraint to an arg index.
// Seems weird to do this in the parser, but I'm not sure how else to.
Expand All @@ -1787,7 +1807,7 @@ fn parse_fn_block_decl(p: parser) -> ast::fn_decl {
[]
} else {
parse_seq(token::BINOP(token::OR), token::BINOP(token::OR),
some(token::COMMA), parse_fn_block_arg, p).node
seq_sep(token::COMMA), parse_fn_block_arg, p).node
};
ret {inputs: inputs,
output: @spanned(p.get_lo_pos(), p.get_hi_pos(), ast::ty_infer),
Expand Down Expand Up @@ -1861,7 +1881,7 @@ fn parse_item_obj(p: parser, attrs: [ast::attribute]) -> @ast::item {
let ident = parse_value_ident(p);
let ty_params = parse_ty_params(p);
let fields: ast::spanned<[ast::obj_field]> =
parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_obj_field, p);
let meths: [@ast::method] = [];
expect(p, token::LBRACE);
Expand Down Expand Up @@ -2063,7 +2083,7 @@ fn parse_item_tag(p: parser, attrs: [ast::attribute]) -> @ast::item {
alt p.peek() {
token::LPAREN. {
let arg_tys = parse_seq(token::LPAREN, token::RPAREN,
some(token::COMMA),
seq_sep(token::COMMA),
{|p| parse_ty(p, false)}, p);
for ty: @ast::ty in arg_tys.node {
args += [{ty: ty, id: p.get_id()}];
Expand Down Expand Up @@ -2255,7 +2275,7 @@ fn parse_meta_item(p: parser) -> @ast::meta_item {
}

fn parse_meta_seq(p: parser) -> [@ast::meta_item] {
ret parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
ret parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_meta_item, p).node;
}

Expand Down Expand Up @@ -2312,7 +2332,7 @@ fn parse_rest_import_name(p: parser, first: ast::ident,
ret spanned(lo, hi, {name: ident, id: p.get_id()});
}
let from_idents_ =
parse_seq(token::LBRACE, token::RBRACE, some(token::COMMA),
parse_seq(token::LBRACE, token::RBRACE, seq_sep(token::COMMA),
parse_import_ident, p).node;
if vec::is_empty(from_idents_) {
p.fatal("at least one import is required");
Expand Down Expand Up @@ -2382,7 +2402,7 @@ fn parse_import(p: parser) -> ast::view_item_ {

fn parse_export(p: parser) -> ast::view_item_ {
let ids =
parse_seq_to_before_end(token::SEMI, option::some(token::COMMA),
parse_seq_to_before_end(token::SEMI, seq_sep(token::COMMA),
parse_ident, p);
ret ast::view_item_export(ids, p.get_id());
}
Expand Down
4 changes: 2 additions & 2 deletions src/comp/syntax/print/pprust.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -294,7 +294,7 @@ fn print_type(s: ps, &&ty: @ast::ty) {
}
fn get_span(f: ast::ty_field) -> codemap::span { ret f.span; }
commasep_cmnt(s, consistent, fields, print_field, get_span);
word(s.s, "}");
word(s.s, ",}");
}
ast::ty_tup(elts) {
popen(s);
Expand Down Expand Up @@ -693,7 +693,7 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
print_expr(s, expr);
end(s);
}
_ { }
_ { word(s.s, ","); }
}
word(s.s, "}");
}
Expand Down
8 changes: 8 additions & 0 deletions src/test/pretty/record-trailing-comma.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
// pp-exact
type thing = {x: int, y: int,};

fn main() {
let sth = {x: 0, y: 1,};
let sth2 = {y: 9 with sth};
assert (sth.x + sth2.y == 9);
}