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