src/libsyntax/ext/deriving/cmp/totaleq.rs

   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::{MetaItem, Item, Expr};
  12 use codemap::Span;
  13 use ext::base::ExtCtxt;
  14 use ext::build::AstBuilder;
  15 use ext::deriving::generic::*;
  16 use ext::deriving::generic::ty::*;
  17 use parse::token::InternedString;
  18
  19 use std::gc::Gc;
  20
  21 pub fn expand_deriving_totaleq(cx: &mut ExtCtxt,
  22                                span: Span,
  23                                mitem: Gc<MetaItem>,
  24                                item: Gc<Item>,
  25                                push: |Gc<Item>|) {
  26     fn cs_total_eq_assert(cx: &mut ExtCtxt, span: Span,
  27                           substr: &Substructure) -> Gc<Expr> {
  28         cs_same_method(|cx, span, exprs| {
  29             // create `a.<method>(); b.<method>(); c.<method>(); ...`
  30             // (where method is `assert_receiver_is_total_eq`)
  31             let stmts = exprs.move_iter().map(|e| cx.stmt_expr(e)).collect();
  32             let block = cx.block(span, stmts, None);
  33             cx.expr_block(block)
  34         },
  35                        |cx, sp, _, _| cx.span_bug(sp, "non matching enums in deriving(Eq)?"),
  36                        cx,
  37                        span,
  38                        substr)
  39     }
  40
  41     let inline = cx.meta_word(span, InternedString::new("inline"));
  42     let hidden = cx.meta_word(span, InternedString::new("hidden"));
  43     let doc = cx.meta_list(span, InternedString::new("doc"), vec!(hidden));
  44     let attrs = vec!(cx.attribute(span, inline),
  45                      cx.attribute(span, doc));
  46     let trait_def = TraitDef {
  47         span: span,
  48         attributes: Vec::new(),
  49         path: Path::new(vec!("std", "cmp", "Eq")),
  50         additional_bounds: Vec::new(),
  51         generics: LifetimeBounds::empty(),
  52         methods: vec!(
  53             MethodDef {
  54                 name: "assert_receiver_is_total_eq",
  55                 generics: LifetimeBounds::empty(),
  56                 explicit_self: borrowed_explicit_self(),
  57                 args: vec!(),
  58                 ret_ty: nil_ty(),
  59                 attributes: attrs,
  60                 const_nonmatching: true,
  61                 combine_substructure: combine_substructure(|a, b, c| {
  62                     cs_total_eq_assert(a, b, c)
  63                 })
  64             }
  65         )
  66     };
  67     trait_def.expand(cx, mitem, item, push)
  68 }