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};
15 use ext::base::ExtCtxt;
16 use ext::build::AstBuilder;
17 use ext::deriving::generic::*;
18 use parse::token::InternedString;
20 pub fn expand_deriving_ord(cx: &mut ExtCtxt,
26 ($name:expr, $op:expr, $equal:expr) => { {
27 let inline = cx.meta_word(span, InternedString::new("inline"));
28 let attrs = vec!(cx.attribute(attr::mk_attr_id(), span, inline));
31 generics: LifetimeBounds::empty(),
32 explicit_self: borrowed_explicit_self(),
33 args: vec!(borrowed_self()),
34 ret_ty: Literal(Path::new(vec!("bool"))),
36 const_nonmatching: false,
37 combine_substructure: combine_substructure(|cx, span, substr| {
38 cs_op($op, $equal, cx, span, substr)
44 let trait_def = TraitDef {
46 attributes: Vec::new(),
47 path: Path::new(vec!("std", "cmp", "Ord")),
48 additional_bounds: Vec::new(),
49 generics: LifetimeBounds::empty(),
51 md!("lt", true, false),
52 md!("le", true, true),
53 md!("gt", false, false),
54 md!("ge", false, true)
57 trait_def.expand(cx, mitem, item, push)
60 /// Strict inequality.
61 fn cs_op(less: bool, equal: bool, cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> @Expr {
62 let op = if less {ast::BiLt} else {ast::BiGt};
65 |cx, span, subexpr, self_f, other_fs| {
67 build up a series of chain ||'s and &&'s from the inside
68 out (hence foldr) to get lexical ordering, i.e. for op ==
72 self.f1 < other.f1 || (!(other.f1 < self.f1) &&
73 (self.f2 < other.f2 || (!(other.f2 < self.f2) &&
79 The optimiser should remove the redundancy. We explicitly
80 get use the binops to avoid auto-deref derefencing too many
81 layers of pointers, if the type includes pointers.
83 let other_f = match other_fs {
85 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")
88 let cmp = cx.expr_binary(span, op, self_f, other_f);
90 let not_cmp = cx.expr_unary(span, ast::UnNot,
91 cx.expr_binary(span, op, other_f, self_f));
93 let and = cx.expr_binary(span, ast::BiAnd, not_cmp, subexpr);
94 cx.expr_binary(span, ast::BiOr, cmp, and)
96 cx.expr_bool(span, equal),
98 // nonmatching enums, order by the order the variants are
102 (other_var, _, _)] =>
109 _ => cx.span_bug(span, "not exactly 2 arguments in `deriving(Ord)`")