diff options
Diffstat (limited to 'src/libsyntax/parse/parser.rs')
| -rw-r--r-- | src/libsyntax/parse/parser.rs | 128 |
1 files changed, 69 insertions, 59 deletions
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 2917ce43358..4330bf8e33b 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1456,11 +1456,12 @@ pub impl Parser { return self.mk_expr(lo, hi, ex); } - + // parse an expression of binops fn parse_binops() -> @expr { - return self.parse_more_binops(self.parse_prefix_expr(), 0); + self.parse_more_binops(self.parse_prefix_expr(), 0) } + // parse an expression of binops of at least min_prec precedence fn parse_more_binops(lhs: @expr, min_prec: uint) -> @expr { if self.expr_is_complete(lhs) { return lhs; } @@ -1468,66 +1469,73 @@ pub impl Parser { if peeked == token::BINOP(token::OR) && (self.restriction == RESTRICT_NO_BAR_OP || self.restriction == RESTRICT_NO_BAR_OR_DOUBLEBAR_OP) { - return lhs; - } - if peeked == token::OROR && + lhs + } else if peeked == token::OROR && self.restriction == RESTRICT_NO_BAR_OR_DOUBLEBAR_OP { - return lhs; - } - let cur_opt = token_to_binop(peeked); - match cur_opt { - Some(cur_op) => { - let cur_prec = operator_prec(cur_op); - if cur_prec > min_prec { - self.bump(); - let expr = self.parse_prefix_expr(); - let rhs = self.parse_more_binops(expr, cur_prec); - self.get_id(); // see ast_util::op_expr_callee_id - let bin = self.mk_expr(lhs.span.lo, rhs.span.hi, - expr_binary(cur_op, lhs, rhs)); - return self.parse_more_binops(bin, min_prec); + lhs + } else { + let cur_opt = token_to_binop(peeked); + match cur_opt { + Some(cur_op) => { + let cur_prec = operator_prec(cur_op); + if cur_prec > min_prec { + self.bump(); + let expr = self.parse_prefix_expr(); + let rhs = self.parse_more_binops(expr, cur_prec); + self.get_id(); // see ast_util::op_expr_callee_id + let bin = self.mk_expr(lhs.span.lo, rhs.span.hi, + expr_binary(cur_op, lhs, rhs)); + self.parse_more_binops(bin, min_prec) + } else { + lhs + } + } + None => { + if as_prec > min_prec && self.eat_keyword(~"as") { + let rhs = self.parse_ty(true); + let _as = self.mk_expr(lhs.span.lo, + rhs.span.hi, + expr_cast(lhs, rhs)); + self.parse_more_binops(_as, min_prec) + } else { + lhs + } + } } - } - _ => () - } - if as_prec > min_prec && self.eat_keyword(~"as") { - let rhs = self.parse_ty(true); - let _as = - self.mk_expr(lhs.span.lo, rhs.span.hi, expr_cast(lhs, rhs)); - return self.parse_more_binops(_as, min_prec); } - return lhs; } - // parse an arbitrary expression. + // parse an assignment expression.... + // actually, this seems to be the main entry point for + // parsing an arbitrary expression. fn parse_assign_expr() -> @expr { let lo = self.span.lo; let lhs = self.parse_binops(); match copy self.token { - token::EQ => { - self.bump(); - let rhs = self.parse_expr(); - return self.mk_expr(lo, rhs.span.hi, expr_assign(lhs, rhs)); + token::EQ => { + self.bump(); + let rhs = self.parse_expr(); + self.mk_expr(lo, rhs.span.hi, expr_assign(lhs, rhs)) } token::BINOPEQ(op) => { - self.bump(); - let rhs = self.parse_expr(); - let mut aop; - match op { - token::PLUS => aop = add, - token::MINUS => aop = subtract, - token::STAR => aop = mul, - token::SLASH => aop = div, - token::PERCENT => aop = rem, - token::CARET => aop = bitxor, - token::AND => aop = bitand, - token::OR => aop = bitor, - token::SHL => aop = shl, - token::SHR => aop = shr - } - self.get_id(); // see ast_util::op_expr_callee_id - return self.mk_expr(lo, rhs.span.hi, - expr_assign_op(aop, lhs, rhs)); + self.bump(); + let rhs = self.parse_expr(); + let mut aop; + match op { + token::PLUS => aop = add, + token::MINUS => aop = subtract, + token::STAR => aop = mul, + token::SLASH => aop = div, + token::PERCENT => aop = rem, + token::CARET => aop = bitxor, + token::AND => aop = bitand, + token::OR => aop = bitor, + token::SHL => aop = shl, + token::SHR => aop = shr + } + self.get_id(); // see ast_util::op_expr_callee_id + self.mk_expr(lo, rhs.span.hi, + expr_assign_op(aop, lhs, rhs)) } token::LARROW => { self.obsolete(copy self.span, ObsoleteBinaryMove); @@ -1535,17 +1543,18 @@ pub impl Parser { self.bump(); // <- self.bump(); // rhs self.bump(); // ; - return self.mk_expr(lo, self.span.hi, - expr_break(None)); + self.mk_expr(lo, self.span.hi, + expr_break(None)) } token::DARROW => { self.bump(); let rhs = self.parse_expr(); - return self.mk_expr(lo, rhs.span.hi, expr_swap(lhs, rhs)); + self.mk_expr(lo, rhs.span.hi, expr_swap(lhs, rhs)) + } + _ => { + lhs } - _ => {/* fall through */ } } - return lhs; } fn parse_if_expr() -> @expr { @@ -1560,7 +1569,7 @@ pub impl Parser { hi = elexpr.span.hi; } let q = {cond: cond, then: thn, els: els, lo: lo, hi: hi}; - return self.mk_expr(q.lo, q.hi, expr_if(q.cond, q.then, q.els)); + f.mk_expr(q.lo, q.hi, expr_if(q.cond, q.then, q.els)) } fn parse_fn_expr(proto: Proto) -> @expr { @@ -1571,8 +1580,9 @@ pub impl Parser { let decl = self.parse_fn_decl(|p| p.parse_arg_or_capture_item()); let body = self.parse_block(); - return self.mk_expr(lo, body.span.hi, - expr_fn(proto, decl, body, @())); + + self.mk_expr(lo, body.span.hi, + expr_fn(proto, decl, body, capture_clause)); } // `|args| { ... }` like in `do` expressions |