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970d7e83 LB |
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. | |
4 | // | |
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. | |
10 | ||
11 | use ast; | |
d9579d0f | 12 | use ast::{MetaItem, Expr}; |
1a4d82fc | 13 | use codemap::Span; |
d9579d0f | 14 | use ext::base::{ExtCtxt, Annotatable}; |
970d7e83 LB |
15 | use ext::build::AstBuilder; |
16 | use ext::deriving::generic::*; | |
1a4d82fc JJ |
17 | use ext::deriving::generic::ty::*; |
18 | use parse::token::InternedString; | |
19 | use ptr::P; | |
970d7e83 | 20 | |
d9579d0f AL |
21 | pub fn expand_deriving_ord(cx: &mut ExtCtxt, |
22 | span: Span, | |
23 | mitem: &MetaItem, | |
62682a34 | 24 | item: &Annotatable, |
d9579d0f | 25 | push: &mut FnMut(Annotatable)) |
1a4d82fc | 26 | { |
d9579d0f AL |
27 | let inline = cx.meta_word(span, InternedString::new("inline")); |
28 | let attrs = vec!(cx.attribute(span, inline)); | |
29 | let trait_def = TraitDef { | |
30 | span: span, | |
31 | attributes: Vec::new(), | |
32 | path: path_std!(cx, core::cmp::Ord), | |
33 | additional_bounds: Vec::new(), | |
34 | generics: LifetimeBounds::empty(), | |
35 | methods: vec!( | |
970d7e83 | 36 | MethodDef { |
d9579d0f | 37 | name: "cmp", |
970d7e83 LB |
38 | generics: LifetimeBounds::empty(), |
39 | explicit_self: borrowed_explicit_self(), | |
1a4d82fc | 40 | args: vec!(borrowed_self()), |
d9579d0f | 41 | ret_ty: Literal(path_std!(cx, core::cmp::Ordering)), |
1a4d82fc | 42 | attributes: attrs, |
62682a34 | 43 | is_unsafe: false, |
d9579d0f AL |
44 | combine_substructure: combine_substructure(Box::new(|a, b, c| { |
45 | cs_cmp(a, b, c) | |
46 | })), | |
970d7e83 | 47 | } |
d9579d0f | 48 | ), |
85aaf69f | 49 | associated_types: Vec::new(), |
970d7e83 | 50 | }; |
1a4d82fc | 51 | |
62682a34 | 52 | trait_def.expand(cx, mitem, item, push) |
1a4d82fc JJ |
53 | } |
54 | ||
d9579d0f AL |
55 | |
56 | pub fn ordering_collapsed(cx: &mut ExtCtxt, | |
57 | span: Span, | |
58 | self_arg_tags: &[ast::Ident]) -> P<ast::Expr> { | |
1a4d82fc JJ |
59 | let lft = cx.expr_ident(span, self_arg_tags[0]); |
60 | let rgt = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[1])); | |
d9579d0f | 61 | cx.expr_method_call(span, lft, cx.ident_of("cmp"), vec![rgt]) |
1a4d82fc JJ |
62 | } |
63 | ||
d9579d0f | 64 | pub fn cs_cmp(cx: &mut ExtCtxt, span: Span, |
1a4d82fc JJ |
65 | substr: &Substructure) -> P<Expr> { |
66 | let test_id = cx.ident_of("__test"); | |
d9579d0f AL |
67 | let equals_path = cx.path_global(span, |
68 | vec!(cx.ident_of_std("core"), | |
69 | cx.ident_of("cmp"), | |
70 | cx.ident_of("Ordering"), | |
71 | cx.ident_of("Equal"))); | |
1a4d82fc | 72 | |
d9579d0f | 73 | let cmp_path = vec![ |
85aaf69f | 74 | cx.ident_of_std("core"), |
1a4d82fc | 75 | cx.ident_of("cmp"), |
d9579d0f AL |
76 | cx.ident_of("Ord"), |
77 | cx.ident_of("cmp"), | |
1a4d82fc JJ |
78 | ]; |
79 | ||
80 | /* | |
81 | Builds: | |
82 | ||
d9579d0f AL |
83 | let __test = ::std::cmp::Ord::cmp(&self_field1, &other_field1); |
84 | if other == ::std::cmp::Ordering::Equal { | |
85 | let __test = ::std::cmp::Ord::cmp(&self_field2, &other_field2); | |
86 | if __test == ::std::cmp::Ordering::Equal { | |
1a4d82fc JJ |
87 | ... |
88 | } else { | |
89 | __test | |
90 | } | |
91 | } else { | |
92 | __test | |
93 | } | |
94 | ||
95 | FIXME #6449: These `if`s could/should be `match`es. | |
96 | */ | |
97 | cs_fold( | |
98 | // foldr nests the if-elses correctly, leaving the first field | |
99 | // as the outermost one, and the last as the innermost. | |
100 | false, | |
101 | |cx, span, old, self_f, other_fs| { | |
102 | // let __test = new; | |
d9579d0f | 103 | // if __test == ::std::cmp::Ordering::Equal { |
1a4d82fc JJ |
104 | // old |
105 | // } else { | |
106 | // __test | |
107 | // } | |
108 | ||
109 | let new = { | |
d9579d0f AL |
110 | let other_f = match (other_fs.len(), other_fs.get(0)) { |
111 | (1, Some(o_f)) => o_f, | |
85aaf69f | 112 | _ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`"), |
1a4d82fc JJ |
113 | }; |
114 | ||
115 | let args = vec![ | |
116 | cx.expr_addr_of(span, self_f), | |
117 | cx.expr_addr_of(span, other_f.clone()), | |
118 | ]; | |
119 | ||
d9579d0f | 120 | cx.expr_call_global(span, cmp_path.clone(), args) |
1a4d82fc JJ |
121 | }; |
122 | ||
123 | let assign = cx.stmt_let(span, false, test_id, new); | |
124 | ||
125 | let cond = cx.expr_binary(span, ast::BiEq, | |
126 | cx.expr_ident(span, test_id), | |
d9579d0f | 127 | cx.expr_path(equals_path.clone())); |
1a4d82fc JJ |
128 | let if_ = cx.expr_if(span, |
129 | cond, | |
130 | old, Some(cx.expr_ident(span, test_id))); | |
131 | cx.expr_block(cx.block(span, vec!(assign), Some(if_))) | |
132 | }, | |
d9579d0f | 133 | cx.expr_path(equals_path.clone()), |
c34b1796 | 134 | Box::new(|cx, span, (self_args, tag_tuple), _non_self_args| { |
1a4d82fc | 135 | if self_args.len() != 2 { |
d9579d0f | 136 | cx.span_bug(span, "not exactly 2 arguments in `derives(Ord)`") |
1a4d82fc | 137 | } else { |
d9579d0f | 138 | ordering_collapsed(cx, span, tag_tuple) |
970d7e83 | 139 | } |
c34b1796 | 140 | }), |
970d7e83 LB |
141 | cx, span, substr) |
142 | } |