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