rust/src/libsyntax/ext/deriving/clone.rs

128 lines
4.4 KiB
Rust

// 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 core::prelude::*;
use ast::{meta_item, item, expr};
use codemap::span;
use ext::base::ExtCtxt;
use ext::build::AstBuilder;
use ext::deriving::generic::*;
pub fn expand_deriving_clone(cx: @ExtCtxt,
span: span,
mitem: @meta_item,
in_items: ~[@item])
-> ~[@item] {
let trait_def = TraitDef {
path: Path::new(~["std", "clone", "Clone"]),
additional_bounds: ~[],
generics: LifetimeBounds::empty(),
methods: ~[
MethodDef {
name: "clone",
generics: LifetimeBounds::empty(),
explicit_self: borrowed_explicit_self(),
args: ~[],
ret_ty: Self,
const_nonmatching: false,
combine_substructure: |c, s, sub| cs_clone("Clone", c, s, sub)
}
]
};
expand_deriving_generic(cx, span,
mitem, in_items,
&trait_def)
}
pub fn expand_deriving_deep_clone(cx: @ExtCtxt,
span: span,
mitem: @meta_item,
in_items: ~[@item])
-> ~[@item] {
let trait_def = TraitDef {
path: Path::new(~["std", "clone", "DeepClone"]),
additional_bounds: ~[],
generics: LifetimeBounds::empty(),
methods: ~[
MethodDef {
name: "deep_clone",
generics: LifetimeBounds::empty(),
explicit_self: borrowed_explicit_self(),
args: ~[],
ret_ty: Self,
const_nonmatching: false,
// cs_clone uses the ident passed to it, i.e. it will
// call deep_clone (not clone) here.
combine_substructure: |c, s, sub| cs_clone("DeepClone", c, s, sub)
}
]
};
expand_deriving_generic(cx, span,
mitem, in_items,
&trait_def)
}
fn cs_clone(
name: &str,
cx: @ExtCtxt, span: span,
substr: &Substructure) -> @expr {
let clone_ident = substr.method_ident;
let ctor_ident;
let all_fields;
let subcall = |field|
cx.expr_method_call(span, field, clone_ident, ~[]);
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(span,
fmt!("Non-matching enum variants in `deriving(%s)`",
name)),
StaticEnum(*) | StaticStruct(*) => cx.span_bug(span,
fmt!("Static method in `deriving(%s)`",
name))
}
match *all_fields {
[(None, _, _), .. _] => {
// enum-like
let subcalls = all_fields.map(|&(_, self_f, _)| subcall(self_f));
cx.expr_call_ident(span, ctor_ident, subcalls)
},
_ => {
// struct-like
let fields = do all_fields.map |&(o_id, self_f, _)| {
let ident = match o_id {
Some(i) => i,
None => cx.span_bug(span,
fmt!("unnamed field in normal struct in `deriving(%s)`",
name))
};
cx.field_imm(span, ident, subcall(self_f))
};
if fields.is_empty() {
// no fields, so construct like `None`
cx.expr_ident(span, ctor_ident)
} else {
cx.expr_struct_ident(span, ctor_ident, fields)
}
}
}
}