bjoernager/rust
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libsyntax: Tighten up expressions in patterns to only allow identifiers or literals (possibly with a minus).

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This had very minimal fallout.
This commit is contained in:
Patrick Walton 2013-05-10 18:19:58 -07:00
parent 5d3559e645
commit db0693ac8d
3 changed files with 53 additions and 26 deletions
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33
src/libsyntax/parse/parser.rs
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@ -915,6 +915,24 @@ pub impl Parser {
codemap::spanned { node: lit, span: mk_sp(lo, self.last_span.hi) }
}
// matches '-' lit | lit
fn parse_literal_maybe_minus(&self) -> @expr {
let minus_lo = self.span.lo;
let minus_present = self.eat(&token::BINOP(token::MINUS));
let lo = self.span.lo;
let literal = @self.parse_lit();
let hi = self.span.hi;
let expr = self.mk_expr(lo, hi, expr_lit(literal));
if minus_present {
let minus_hi = self.span.hi;
self.mk_expr(minus_lo, minus_hi, expr_unary(neg, expr))
} else {
expr
}
}
// parse a path into a vector of idents, whether the path starts
// with ::, and a span.
fn parse_path(&self) -> (~[ast::ident],bool,span) {
@ -2360,10 +2378,19 @@ pub impl Parser {
|| self.is_keyword(&~"true")
|| self.is_keyword(&~"false")
{
// parse an expression pattern or exp .. exp
let val = self.parse_expr_res(RESTRICT_NO_BAR_OP);
// Parse an expression pattern or exp .. exp.
//
// These expressions are limited to literals (possibly
// preceded by unary-minus) or identifiers.
let val = self.parse_literal_maybe_minus();
if self.eat(&token::DOTDOT) {
let end = self.parse_expr_res(RESTRICT_NO_BAR_OP);
let end = if is_ident_or_path(&tok) {
let path = self.parse_path_with_tps(true);
let hi = self.span.hi;
self.mk_expr(lo, hi, expr_path(path))
} else {
self.parse_literal_maybe_minus()
};
pat = pat_range(val, end);
} else {
pat = pat_lit(val);