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::*;
20 pub fn expand_deriving_ord(cx: &mut ExtCtxt,
26 ($name:expr, $op:expr, $equal:expr) => {
29 generics: LifetimeBounds::empty(),
30 explicit_self: borrowed_explicit_self(),
31 args: vec!(borrowed_self()),
32 ret_ty: Literal(Path::new(vec!("bool"))),
34 const_nonmatching: false,
35 combine_substructure: |cx, span, substr| cs_op($op, $equal, cx, span, substr)
40 let trait_def = TraitDef {
42 attributes: Vec::new(),
43 path: Path::new(vec!("std", "cmp", "Ord")),
44 additional_bounds: Vec::new(),
45 generics: LifetimeBounds::empty(),
47 md!("lt", true, false),
48 md!("le", true, true),
49 md!("gt", false, false),
50 md!("ge", false, true)
53 trait_def.expand(cx, mitem, item, push)
56 /// Strict inequality.
57 fn cs_op(less: bool, equal: bool, cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> @Expr {
58 let op = if less {ast::BiLt} else {ast::BiGt};
61 |cx, span, subexpr, self_f, other_fs| {
63 build up a series of chain ||'s and &&'s from the inside
64 out (hence foldr) to get lexical ordering, i.e. for op ==
68 self.f1 < other.f1 || (!(other.f1 < self.f1) &&
69 (self.f2 < other.f2 || (!(other.f2 < self.f2) &&
75 The optimiser should remove the redundancy. We explicitly
76 get use the binops to avoid auto-deref derefencing too many
77 layers of pointers, if the type includes pointers.
79 let other_f = match other_fs {
81 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")
84 let cmp = cx.expr_binary(span, op, self_f, other_f);
86 let not_cmp = cx.expr_unary(span, ast::UnNot,
87 cx.expr_binary(span, op, other_f, self_f));
89 let and = cx.expr_binary(span, ast::BiAnd, not_cmp, subexpr);
90 cx.expr_binary(span, ast::BiOr, cmp, and)
92 cx.expr_bool(span, equal),
94 // nonmatching enums, order by the order the variants are
105 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")