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// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use deriving::generic::*;
use deriving::generic::ty::*;
use syntax::ast::{MetaItem, Expr};
use syntax::codemap::Span;
use syntax::ext::base::{ExtCtxt, Annotatable};
use syntax::ext::build::AstBuilder;
use syntax::parse::token::InternedString;
use syntax::ptr::P;
pub fn expand_deriving_clone(cx: &mut ExtCtxt,
span: Span,
mitem: &MetaItem,
item: &Annotatable,
push: &mut FnMut(Annotatable))
{
let inline = cx.meta_word(span, InternedString::new("inline"));
let attrs = vec!(cx.attribute(span, inline));
let trait_def = TraitDef {
span: span,
attributes: Vec::new(),
path: path_std!(cx, core::clone::Clone),
additional_bounds: Vec::new(),
generics: LifetimeBounds::empty(),
is_unsafe: false,
methods: vec!(
MethodDef {
name: "clone",
generics: LifetimeBounds::empty(),
explicit_self: borrowed_explicit_self(),
args: Vec::new(),
ret_ty: Self_,
attributes: attrs,
is_unsafe: false,
combine_substructure: combine_substructure(Box::new(|c, s, sub| {
cs_clone("Clone", c, s, sub)
})),
}
),
associated_types: Vec::new(),
};
trait_def.expand(cx, mitem, item, push)
}
fn cs_clone(
name: &str,
cx: &mut ExtCtxt, trait_span: Span,
substr: &Substructure) -> P<Expr> {
let ctor_path;
let all_fields;
let fn_path = cx.std_path(&["clone", "Clone", "clone"]);
let subcall = |field: &FieldInfo| {
let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
cx.expr_call_global(field.span, fn_path.clone(), args)
};
match *substr.fields {
Struct(ref af) => {
ctor_path = cx.path(trait_span, vec![substr.type_ident]);
all_fields = af;
}
EnumMatching(_, variant, ref af) => {
ctor_path = cx.path(trait_span, vec![substr.type_ident, variant.node.name]);
all_fields = af;
},
EnumNonMatchingCollapsed (..) => {
cx.span_bug(trait_span,
&format!("non-matching enum variants in \
`derive({})`", name))
}
StaticEnum(..) | StaticStruct(..) => {
cx.span_bug(trait_span,
&format!("static method in `derive({})`", name))
}
}
if !all_fields.is_empty() && all_fields[0].name.is_none() {
// enum-like
let subcalls = all_fields.iter().map(subcall).collect();
let path = cx.expr_path(ctor_path);
cx.expr_call(trait_span, path, subcalls)
} else {
// struct-like
let fields = all_fields.iter().map(|field| {
let ident = match field.name {
Some(i) => i,
None => {
cx.span_bug(trait_span,
&format!("unnamed field in normal struct in \
`derive({})`", name))
}
};
cx.field_imm(field.span, ident, subcall(field))
}).collect::<Vec<_>>();
if fields.is_empty() {
// no fields, so construct like `None`
cx.expr_path(ctor_path)
} else {
cx.expr_struct(trait_span, ctor_path, fields)
}
}
}
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