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::*;
17 use parse::token::InternedString;
19 pub fn expand_deriving_ord(cx: &mut ExtCtxt,
25 ($name:expr, $op:expr, $equal:expr) => { {
26 let inline = cx.meta_word(span, InternedString::new("inline"));
27 let attrs = vec!(cx.attribute(span, inline));
30 generics: LifetimeBounds::empty(),
31 explicit_self: borrowed_explicit_self(),
32 args: vec!(borrowed_self()),
33 ret_ty: Literal(Path::new(vec!("bool"))),
35 const_nonmatching: false,
36 combine_substructure: combine_substructure(|cx, span, substr| {
37 cs_op($op, $equal, cx, span, substr)
43 let trait_def = TraitDef {
45 attributes: Vec::new(),
46 path: Path::new(vec!("std", "cmp", "Ord")),
47 additional_bounds: Vec::new(),
48 generics: LifetimeBounds::empty(),
50 md!("lt", true, false),
51 md!("le", true, true),
52 md!("gt", false, false),
53 md!("ge", false, true)
56 trait_def.expand(cx, mitem, item, push)
59 /// Strict inequality.
60 fn cs_op(less: bool, equal: bool, cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> @Expr {
61 let op = if less {ast::BiLt} else {ast::BiGt};
64 |cx, span, subexpr, self_f, other_fs| {
66 build up a series of chain ||'s and &&'s from the inside
67 out (hence foldr) to get lexical ordering, i.e. for op ==
71 self.f1 < other.f1 || (!(other.f1 < self.f1) &&
72 (self.f2 < other.f2 || (!(other.f2 < self.f2) &&
78 The optimiser should remove the redundancy. We explicitly
79 get use the binops to avoid auto-deref derefencing too many
80 layers of pointers, if the type includes pointers.
82 let other_f = match other_fs {
84 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")
87 let cmp = cx.expr_binary(span, op, self_f, other_f);
89 let not_cmp = cx.expr_unary(span, ast::UnNot,
90 cx.expr_binary(span, op, other_f, self_f));
92 let and = cx.expr_binary(span, ast::BiAnd, not_cmp, subexpr);
93 cx.expr_binary(span, ast::BiOr, cmp, and)
95 cx.expr_bool(span, equal),
97 // nonmatching enums, order by the order the variants are
101 (other_var, _, _)] =>
108 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")