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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 ast::{MetaItem, Item, Expr};
use codemap::Span;
use ext::base::ExtCtxt;
use ext::build::AstBuilder;
use ext::deriving::generic::*;
pub fn expand_deriving_clone(cx: &mut ExtCtxt,
span: Span,
mitem: @MetaItem,
item: @Item,
push: |@Item|) {
let trait_def = TraitDef {
span: span,
attributes: Vec::new(),
path: Path::new(vec!("std", "clone", "Clone")),
additional_bounds: Vec::new(),
generics: LifetimeBounds::empty(),
methods: vec!(
MethodDef {
name: "clone",
generics: LifetimeBounds::empty(),
explicit_self: borrowed_explicit_self(),
args: Vec::new(),
ret_ty: Self,
inline: true,
const_nonmatching: false,
combine_substructure: |c, s, sub| cs_clone("Clone", c, s, sub)
}
)
};
trait_def.expand(cx, mitem, item, push)
}
fn cs_clone(
name: &str,
cx: &mut ExtCtxt, trait_span: Span,
substr: &Substructure) -> @Expr {
let clone_ident = substr.method_ident;
let ctor_ident;
let all_fields;
let subcall = |field: &FieldInfo|
cx.expr_method_call(field.span, field.self_, clone_ident, Vec::new());
match *substr.fields {
Struct(ref af) => {
ctor_ident = substr.type_ident;
all_fields = af;
}
EnumMatching(_, variant, ref af) => {
ctor_ident = variant.node.name;
all_fields = af;
},
EnumNonMatching(..) => cx.span_bug(trait_span,
format!("non-matching enum variants in `deriving({})`",
name)),
StaticEnum(..) | StaticStruct(..) => cx.span_bug(trait_span,
format!("static method in `deriving({})`",
name))
}
if all_fields.len() >= 1 && all_fields.get(0).name.is_none() {
// enum-like
let subcalls = all_fields.iter().map(subcall).collect();
cx.expr_call_ident(trait_span, ctor_ident, 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 `deriving({})`",
name))
};
cx.field_imm(field.span, ident, subcall(field))
}).collect::<Vec<_>>();
if fields.is_empty() {
// no fields, so construct like `None`
cx.expr_ident(trait_span, ctor_ident)
} else {
cx.expr_struct_ident(trait_span, ctor_ident, fields)
}
}
}
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