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rustc: Parse field and vector indexing expressions

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This commit is contained in:
Patrick Walton 2010-10-14 17:42:06 -07:00
parent ff4e9f9141
commit 5826a2e3de
1 changed files with 53 additions and 34 deletions
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87
src/comp/front/parser.rs
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@ -226,6 +226,43 @@ io fn parse_name(parser p, ast.ident id) -> ast.name {
ret spanned(lo, tys.span, rec(ident=id, types=tys.node));
}
/** Parses any field or index selectors. */
io fn parse_selectors(parser p, @ast.expr ex) -> @ast.expr {
if (p.peek() == token.DOT) {
auto lo = p.get_span();
p.bump();
alt (p.peek()) {
case (token.LPAREN) {
p.bump();
auto idx = parse_expr(p);
expect(p, token.RPAREN);
auto hi = p.get_span();
auto lval = @spanned(lo, hi, ast.lval_index(ex, idx));
auto lval_ex = @spanned(lo, hi, ast.expr_lval(lval));
ret parse_selectors(p, lval_ex);
}
case (token.IDENT(?ident)) {
p.bump();
auto hi = p.get_span();
auto lval = @spanned(lo, hi, ast.lval_field(ex, ident));
auto lval_ex = @spanned(lo, hi, ast.expr_lval(lval));
ret parse_selectors(p, lval_ex);
}
case (_) {
p.err("expecting '(' or field name after identifier");
}
}
}
ret ex;
}
io fn parse_possibly_mutable_expr(parser p) -> tup(bool, @ast.expr) {
auto mut;
if (p.peek() == token.MUTABLE) {
@ -238,25 +275,6 @@ io fn parse_possibly_mutable_expr(parser p) -> tup(bool, @ast.expr) {
ret tup(mut, parse_expr(p));
}
io fn parse_lval(parser p) -> option[@ast.lval] {
auto lo = p.get_span();
alt (p.peek()) {
case (token.IDENT(?i)) {
auto n = parse_name(p, i);
auto hi = n.span;
auto lval = ast.lval_name(n, none[ast.referent]);
ret some(@spanned(lo, hi, lval));
}
case (_) {
ret none[@ast.lval];
}
}
fail;
}
io fn parse_bottom_expr(parser p) -> @ast.expr {
auto lo = p.get_span();
@ -316,27 +334,28 @@ io fn parse_bottom_expr(parser p) -> @ast.expr {
ex = ast.expr_rec(es.node);
}
case (token.IDENT(?i)) {
auto n = parse_name(p, i);
hi = p.get_span();
auto lval = ast.lval_name(n, none[ast.referent]);
auto lval_sp = @spanned(lo, hi, lval);
ex = ast.expr_lval(lval_sp);
}
case (_) {
alt (parse_lval(p)) {
case (some[@ast.lval](?lval)) {
hi = lval.span;
ex = ast.expr_lval(lval);
alt (parse_lit(p)) {
case (some[ast.lit](?lit)) {
hi = lit.span;
ex = ast.expr_lit(@lit);
}
case (none[@ast.lval]) {
alt (parse_lit(p)) {
case (some[ast.lit](?lit)) {
hi = lit.span;
ex = ast.expr_lit(@lit);
}
case (none[ast.lit]) {
p.err("expecting expression");
}
}
case (none[ast.lit]) {
p.err("expecting expression");
}
}
}
}
ret @spanned(lo, hi, ex);
ret parse_selectors(p, @spanned(lo, hi, ex));
}
io fn parse_path_expr(parser p) -> @ast.expr {