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1 | // Copyright 2015 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 | // force-host | |
12 | ||
13 | #![feature(plugin_registrar)] | |
14 | #![feature(box_syntax)] | |
15 | #![feature(rustc_private)] | |
16 | ||
17 | extern crate syntax; | |
18 | extern crate rustc; | |
19 | ||
20 | use syntax::ast; | |
21 | use syntax::attr::AttrMetaMethods; | |
22 | use syntax::codemap::Span; | |
23 | use syntax::ext::base::{MultiDecorator, ExtCtxt, Annotatable}; | |
24 | use syntax::ext::build::AstBuilder; | |
25 | use syntax::ext::deriving::generic::{cs_fold, TraitDef, MethodDef, combine_substructure}; | |
26 | use syntax::ext::deriving::generic::{Substructure, Struct, EnumMatching}; | |
27 | use syntax::ext::deriving::generic::ty::{Literal, LifetimeBounds, Path, borrowed_explicit_self}; | |
28 | use syntax::parse::token; | |
29 | use syntax::ptr::P; | |
30 | use rustc::plugin::Registry; | |
31 | ||
32 | #[plugin_registrar] | |
33 | pub fn plugin_registrar(reg: &mut Registry) { | |
34 | reg.register_syntax_extension( | |
35 | token::intern("derive_TotalSum"), | |
36 | MultiDecorator(box expand)); | |
37 | } | |
38 | ||
39 | fn expand(cx: &mut ExtCtxt, | |
40 | span: Span, | |
41 | mitem: &ast::MetaItem, | |
62682a34 | 42 | item: &Annotatable, |
d9579d0f AL |
43 | push: &mut FnMut(Annotatable)) { |
44 | let trait_def = TraitDef { | |
45 | span: span, | |
46 | attributes: vec![], | |
47 | path: Path::new(vec!["TotalSum"]), | |
48 | additional_bounds: vec![], | |
49 | generics: LifetimeBounds::empty(), | |
50 | associated_types: vec![], | |
51 | methods: vec![ | |
52 | MethodDef { | |
53 | name: "total_sum", | |
54 | generics: LifetimeBounds::empty(), | |
55 | explicit_self: borrowed_explicit_self(), | |
56 | args: vec![], | |
57 | ret_ty: Literal(Path::new_local("isize")), | |
58 | attributes: vec![], | |
62682a34 | 59 | is_unsafe: false, |
d9579d0f AL |
60 | combine_substructure: combine_substructure(Box::new(totalsum_substructure)), |
61 | }, | |
62 | ], | |
63 | }; | |
64 | ||
62682a34 | 65 | trait_def.expand(cx, mitem, item, push) |
d9579d0f AL |
66 | } |
67 | ||
68 | // Mostly copied from syntax::ext::deriving::hash | |
69 | /// Defines how the implementation for `trace()` is to be generated | |
70 | fn totalsum_substructure(cx: &mut ExtCtxt, trait_span: Span, | |
71 | substr: &Substructure) -> P<ast::Expr> { | |
72 | let fields = match *substr.fields { | |
73 | Struct(ref fs) | EnumMatching(_, _, ref fs) => fs, | |
74 | _ => cx.span_bug(trait_span, "impossible substructure") | |
75 | }; | |
76 | ||
77 | fields.iter().fold(cx.expr_isize(trait_span, 0), |acc, ref item| { | |
78 | if item.attrs.iter().find(|a| a.check_name("ignore")).is_some() { | |
79 | acc | |
80 | } else { | |
81 | cx.expr_binary(item.span, ast::BiAdd, acc, | |
82 | cx.expr_method_call(item.span, | |
83 | item.self_.clone(), | |
84 | substr.method_ident, | |
85 | Vec::new())) | |
86 | } | |
87 | }) | |
88 | } |