88 lines
3.6 KiB
Rust
88 lines
3.6 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use deriving::path_std;
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use deriving::generic::*;
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use deriving::generic::ty::*;
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use syntax::ast::{self, Expr, MetaItem};
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use syntax::ext::base::{Annotatable, ExtCtxt};
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use syntax::ext::build::AstBuilder;
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use syntax::ptr::P;
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use syntax::symbol::Symbol;
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use syntax_pos::Span;
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pub fn expand_deriving_eq(cx: &mut ExtCtxt,
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span: Span,
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mitem: &MetaItem,
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item: &Annotatable,
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push: &mut FnMut(Annotatable)) {
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let inline = cx.meta_word(span, Symbol::intern("inline"));
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let hidden = cx.meta_list_item_word(span, Symbol::intern("hidden"));
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let doc = cx.meta_list(span, Symbol::intern("doc"), vec![hidden]);
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let attrs = vec![cx.attribute(span, inline), cx.attribute(span, doc)];
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let trait_def = TraitDef {
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span,
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attributes: Vec::new(),
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path: path_std!(cx, cmp::Eq),
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additional_bounds: Vec::new(),
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generics: LifetimeBounds::empty(),
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is_unsafe: false,
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supports_unions: true,
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methods: vec![MethodDef {
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name: "assert_receiver_is_total_eq",
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generics: LifetimeBounds::empty(),
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explicit_self: borrowed_explicit_self(),
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args: vec![],
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ret_ty: nil_ty(),
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attributes: attrs,
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is_unsafe: false,
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unify_fieldless_variants: true,
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combine_substructure: combine_substructure(Box::new(|a, b, c| {
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cs_total_eq_assert(a, b, c)
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})),
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}],
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associated_types: Vec::new(),
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};
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trait_def.expand_ext(cx, mitem, item, push, true)
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}
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fn cs_total_eq_assert(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
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fn assert_ty_bounds(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>,
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ty: P<ast::Ty>, span: Span, helper_name: &str) {
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// Generate statement `let _: helper_name<ty>;`,
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// set the expn ID so we can use the unstable struct.
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let span = span.with_ctxt(cx.backtrace());
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let assert_path = cx.path_all(span, true,
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cx.std_path(&["cmp", helper_name]),
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vec![], vec![ty], vec![]);
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stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
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}
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fn process_variant(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>, variant: &ast::VariantData) {
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for field in variant.fields() {
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// let _: AssertParamIsEq<FieldTy>;
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assert_ty_bounds(cx, stmts, field.ty.clone(), field.span, "AssertParamIsEq");
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}
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}
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let mut stmts = Vec::new();
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match *substr.fields {
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StaticStruct(vdata, ..) => {
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process_variant(cx, &mut stmts, vdata);
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}
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StaticEnum(enum_def, ..) => {
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for variant in &enum_def.variants {
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process_variant(cx, &mut stmts, &variant.node.data);
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}
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}
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_ => cx.span_bug(trait_span, "unexpected substructure in `derive(Eq)`")
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}
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cx.expr_block(cx.block(trait_span, stmts))
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}
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