1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use ast::{MetaItem, Item, Expr};
14 use ext::base::ExtCtxt;
15 use ext::build::AstBuilder;
16 use ext::deriving::generic::*;
18 pub fn expand_deriving_ord(cx: &mut ExtCtxt,
24 ($name:expr, $op:expr, $equal:expr) => {
27 generics: LifetimeBounds::empty(),
28 explicit_self: borrowed_explicit_self(),
29 args: ~[borrowed_self()],
30 ret_ty: Literal(Path::new(~["bool"])),
32 const_nonmatching: false,
33 combine_substructure: |cx, span, substr| cs_op($op, $equal, cx, span, substr)
38 let trait_def = TraitDef {
40 path: Path::new(~["std", "cmp", "Ord"]),
41 additional_bounds: ~[],
42 generics: LifetimeBounds::empty(),
44 md!("lt", true, false),
45 md!("le", true, true),
46 md!("gt", false, false),
47 md!("ge", false, true)
50 trait_def.expand(cx, mitem, item, push)
53 /// Strict inequality.
54 fn cs_op(less: bool, equal: bool, cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> @Expr {
55 let op = if less {ast::BiLt} else {ast::BiGt};
58 |cx, span, subexpr, self_f, other_fs| {
60 build up a series of chain ||'s and &&'s from the inside
61 out (hence foldr) to get lexical ordering, i.e. for op ==
65 self.f1 < other.f1 || (!(other.f1 < self.f1) &&
66 (self.f2 < other.f2 || (!(other.f2 < self.f2) &&
72 The optimiser should remove the redundancy. We explicitly
73 get use the binops to avoid auto-deref derefencing too many
74 layers of pointers, if the type includes pointers.
76 let other_f = match other_fs {
78 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")
81 let cmp = cx.expr_binary(span, op, self_f, other_f);
83 let not_cmp = cx.expr_unary(span, ast::UnNot,
84 cx.expr_binary(span, op, other_f, self_f));
86 let and = cx.expr_binary(span, ast::BiAnd, not_cmp, subexpr);
87 cx.expr_binary(span, ast::BiOr, cmp, and)
89 cx.expr_bool(span, equal),
91 // nonmatching enums, order by the order the variants are
102 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")