107 lines
3.9 KiB
Rust
107 lines
3.9 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_local, path_std};
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use deriving::generic::*;
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use deriving::generic::ty::*;
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use syntax::ast::{BinOpKind, 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_partial_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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// structures are equal if all fields are equal, and non equal, if
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// any fields are not equal or if the enum variants are different
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fn cs_eq(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
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cs_fold(true, // use foldl
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|cx, span, subexpr, self_f, other_fs| {
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let other_f = match (other_fs.len(), other_fs.get(0)) {
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(1, Some(o_f)) => o_f,
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_ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`"),
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};
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let eq = cx.expr_binary(span, BinOpKind::Eq, self_f, other_f.clone());
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cx.expr_binary(span, BinOpKind::And, subexpr, eq)
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},
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cx.expr_bool(span, true),
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Box::new(|cx, span, _, _| cx.expr_bool(span, false)),
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cx,
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span,
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substr)
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}
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fn cs_ne(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
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cs_fold(true, // use foldl
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|cx, span, subexpr, self_f, other_fs| {
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let other_f = match (other_fs.len(), other_fs.get(0)) {
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(1, Some(o_f)) => o_f,
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_ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`"),
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};
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let eq = cx.expr_binary(span, BinOpKind::Ne, self_f, other_f.clone());
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cx.expr_binary(span, BinOpKind::Or, subexpr, eq)
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},
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cx.expr_bool(span, false),
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Box::new(|cx, span, _, _| cx.expr_bool(span, true)),
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cx,
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span,
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substr)
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}
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macro_rules! md {
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($name:expr, $f:ident) => { {
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let inline = cx.meta_word(span, Symbol::intern("inline"));
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let attrs = vec![cx.attribute(span, inline)];
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MethodDef {
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name: $name,
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generics: LifetimeBounds::empty(),
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explicit_self: borrowed_explicit_self(),
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args: vec![borrowed_self()],
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ret_ty: Literal(path_local!(bool)),
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attributes: attrs,
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is_unsafe: false,
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unify_fieldless_variants: true,
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combine_substructure: combine_substructure(Box::new(|a, b, c| {
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$f(a, b, c)
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}))
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}
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} }
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}
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// avoid defining `ne` if we can
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// c-like enums, enums without any fields and structs without fields
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// can safely define only `eq`.
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let mut methods = vec![md!("eq", cs_eq)];
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if !is_type_without_fields(item) {
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methods.push(md!("ne", cs_ne));
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}
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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::PartialEq),
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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: false,
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methods,
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associated_types: Vec::new(),
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};
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trait_def.expand(cx, mitem, item, push)
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}
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