bjoernager/rust
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Teach ast and parser about linear for expressions.

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This commit is contained in:
Graydon Hoare 2011-01-20 13:11:47 -08:00
parent 9d3ebd6a57
commit 33b342e891
2 changed files with 57 additions and 29 deletions
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85
src/comp/front/parser.rs
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@ -891,6 +891,29 @@ impure fn parse_if_expr(parser p) -> @ast.expr {
ret @spanned(lo, hi, ast.expr_if(cond, thn, els, ast.ann_none));
}
impure fn parse_for_expr(parser p) -> @ast.expr {
auto lo = p.get_span();
auto hi = lo;
expect(p, token.FOR);
expect (p, token.LPAREN);
let @ast.local local;
if (p.peek() == token.AUTO) {
p.bump();
local = parse_auto_local(p);
} else {
local = parse_typed_local(p);
}
expect(p, token.IN);
auto seq = parse_expr(p);
expect(p, token.RPAREN);
auto body = parse_block(p);
hi = body.span;
ret @spanned(lo, hi, ast.expr_for(local, seq, body, ast.ann_none));
}
impure fn parse_while_expr(parser p) -> @ast.expr {
auto lo = p.get_span();
auto hi = lo;
@ -979,6 +1002,9 @@ impure fn parse_expr_inner(parser p) -> @ast.expr {
case (token.IF) {
ret parse_if_expr(p);
}
case (token.FOR) {
ret parse_for_expr(p);
}
case (token.WHILE) {
ret parse_while_expr(p);
}
@ -1052,43 +1078,40 @@ impure fn parse_pat(parser p) -> @ast.pat {
ret @spanned(lo, hi, pat);
}
impure fn parse_let(parser p) -> @ast.decl {
auto lo = p.get_span();
expect(p, token.LET);
auto ty = parse_ty(p);
impure fn parse_local(&option.t[@ast.ty] tyopt, parser p) -> @ast.local {
auto ident = parse_ident(p);
auto init = parse_initializer(p);
ret @rec(ty = tyopt,
infer = false,
ident = ident,
init = init,
id = p.next_def_id(),
ann = ast.ann_none);
}
impure fn parse_typed_local(parser p) -> @ast.local {
auto ty = parse_ty(p);
ret parse_local(some(ty), p);
}
impure fn parse_auto_local(parser p) -> @ast.local {
ret parse_local(none[@ast.ty], p);
}
impure fn parse_let(parser p) -> @ast.decl {
auto lo = p.get_span();
expect(p, token.LET);
auto local = parse_typed_local(p);
auto hi = p.get_span();
let ast.local local = rec(ty = some(ty),
infer = false,
ident = ident,
init = init,
id = p.next_def_id(),
ann = ast.ann_none);
ret @spanned(lo, hi, ast.decl_local(@local));
ret @spanned(lo, hi, ast.decl_local(local));
}
impure fn parse_auto(parser p) -> @ast.decl {
auto lo = p.get_span();
expect(p, token.AUTO);
auto ident = parse_ident(p);
auto init = parse_initializer(p);
auto local = parse_auto_local(p);
auto hi = p.get_span();
let ast.local local = rec(ty = none[@ast.ty],
infer = true,
ident = ident,
init = init,
id = p.next_def_id(),
ann = ast.ann_none);
ret @spanned(lo, hi, ast.decl_local(@local));
ret @spanned(lo, hi, ast.decl_local(local));
}
impure fn parse_stmt(parser p) -> @ast.stmt {
@ -1150,6 +1173,11 @@ impure fn parse_stmt(parser p) -> @ast.stmt {
ret @spanned(lo, e.span, ast.stmt_expr(e));
}
case (token.FOR) {
auto e = parse_expr(p);
ret @spanned(lo, e.span, ast.stmt_expr(e));
}
case (token.WHILE) {
auto e = parse_expr(p);
ret @spanned(lo, e.span, ast.stmt_expr(e));
@ -1279,6 +1307,7 @@ fn stmt_ends_with_semi(@ast.stmt stmt) -> bool {
case (ast.expr_lit(_,_)) { ret true; }
case (ast.expr_cast(_,_,_)) { ret true; }
case (ast.expr_if(_,_,_,_)) { ret false; }
case (ast.expr_for(_,_,_,_)) { ret false; }
case (ast.expr_while(_,_,_)) { ret false; }
case (ast.expr_do_while(_,_,_)) { ret false; }
case (ast.expr_alt(_,_,_)) { ret false; }
@ -1289,10 +1318,8 @@ fn stmt_ends_with_semi(@ast.stmt stmt) -> bool {
case (ast.expr_field(_,_,_)) { ret true; }
case (ast.expr_index(_,_,_)) { ret true; }
case (ast.expr_path(_,_,_)) { ret true; }
case (_) { fail; }
}
}
case (_) { fail; }
}
}