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use deriving::generic::*;
use deriving::generic::ty::*;
use syntax::ast::{BinOpKind, Expr, MetaItem};
use syntax::ext::base::{Annotatable, ExtCtxt};
use syntax::ext::build::AstBuilder;
use syntax::ptr::P;
use syntax::symbol::Symbol;
use syntax_pos::Span;
pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt,
span: Span,
mitem: &MetaItem,
item: &Annotatable,
push: &mut FnMut(Annotatable)) {
fn cs_eq(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
cs_fold(true,
|cx, span, subexpr, self_f, other_fs| {
let other_f = match (other_fs.len(), other_fs.get(0)) {
(1, Some(o_f)) => o_f,
_ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`"),
};
let eq = cx.expr_binary(span, BinOpKind::Eq, self_f, other_f.clone());
cx.expr_binary(span, BinOpKind::And, subexpr, eq)
},
cx.expr_bool(span, true),
Box::new(|cx, span, _, _| cx.expr_bool(span, false)),
cx,
span,
substr)
}
fn cs_ne(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
cs_fold(true,
|cx, span, subexpr, self_f, other_fs| {
let other_f = match (other_fs.len(), other_fs.get(0)) {
(1, Some(o_f)) => o_f,
_ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`"),
};
let eq = cx.expr_binary(span, BinOpKind::Ne, self_f, other_f.clone());
cx.expr_binary(span, BinOpKind::Or, subexpr, eq)
},
cx.expr_bool(span, false),
Box::new(|cx, span, _, _| cx.expr_bool(span, true)),
cx,
span,
substr)
}
macro_rules! md {
($name:expr, $f:ident) => { {
let inline = cx.meta_word(span, Symbol::intern("inline"));
let attrs = vec![cx.attribute(span, inline)];
MethodDef {
name: $name,
generics: LifetimeBounds::empty(),
explicit_self: borrowed_explicit_self(),
args: vec![borrowed_self()],
ret_ty: Literal(path_local!(bool)),
attributes: attrs,
is_unsafe: false,
unify_fieldless_variants: true,
combine_substructure: combine_substructure(Box::new(|a, b, c| {
$f(a, b, c)
}))
}
} }
}
let mut methods = vec![md!("eq", cs_eq)];
if !is_type_without_fields(item) {
methods.push(md!("ne", cs_ne));
}
let trait_def = TraitDef {
span: span,
attributes: Vec::new(),
path: path_std!(cx, core::cmp::PartialEq),
additional_bounds: Vec::new(),
generics: LifetimeBounds::empty(),
is_unsafe: false,
supports_unions: false,
methods: methods,
associated_types: Vec::new(),
};
trait_def.expand(cx, mitem, item, push)
}