111 lines
3.8 KiB
Rust
111 lines
3.8 KiB
Rust
// Copyright 2012-2013 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 ast::{MetaItem, Item, Expr};
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use codemap::Span;
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use ext::base::ExtCtxt;
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use ext::build::AstBuilder;
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use ext::deriving::generic::*;
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use ext::deriving::generic::ty::*;
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use parse::token::InternedString;
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use std::gc::Gc;
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pub fn expand_deriving_clone(cx: &mut ExtCtxt,
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span: Span,
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mitem: Gc<MetaItem>,
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item: Gc<Item>,
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push: |Gc<Item>|) {
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let inline = cx.meta_word(span, InternedString::new("inline"));
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let attrs = vec!(cx.attribute(span, inline));
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let trait_def = TraitDef {
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span: span,
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attributes: Vec::new(),
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path: Path::new(vec!("std", "clone", "Clone")),
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additional_bounds: Vec::new(),
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generics: LifetimeBounds::empty(),
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methods: vec!(
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MethodDef {
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name: "clone",
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generics: LifetimeBounds::empty(),
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explicit_self: borrowed_explicit_self(),
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args: Vec::new(),
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ret_ty: Self,
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attributes: attrs,
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const_nonmatching: false,
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combine_substructure: combine_substructure(|c, s, sub| {
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cs_clone("Clone", c, s, sub)
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}),
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}
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)
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};
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trait_def.expand(cx, mitem, item, push)
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}
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fn cs_clone(
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name: &str,
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cx: &mut ExtCtxt, trait_span: Span,
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substr: &Substructure) -> Gc<Expr> {
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let clone_ident = substr.method_ident;
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let ctor_ident;
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let all_fields;
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let subcall = |field: &FieldInfo|
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cx.expr_method_call(field.span, field.self_, clone_ident, Vec::new());
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match *substr.fields {
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Struct(ref af) => {
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ctor_ident = substr.type_ident;
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all_fields = af;
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}
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EnumMatching(_, variant, ref af) => {
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ctor_ident = variant.node.name;
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all_fields = af;
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},
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EnumNonMatching(..) => {
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cx.span_bug(trait_span,
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format!("non-matching enum variants in \
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`deriving({})`",
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name).as_slice())
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}
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StaticEnum(..) | StaticStruct(..) => {
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cx.span_bug(trait_span,
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format!("static method in `deriving({})`",
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name).as_slice())
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}
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}
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if all_fields.len() >= 1 && all_fields.get(0).name.is_none() {
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// enum-like
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let subcalls = all_fields.iter().map(subcall).collect();
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cx.expr_call_ident(trait_span, ctor_ident, subcalls)
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} else {
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// struct-like
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let fields = all_fields.iter().map(|field| {
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let ident = match field.name {
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Some(i) => i,
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None => {
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cx.span_bug(trait_span,
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format!("unnamed field in normal struct in \
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`deriving({})`",
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name).as_slice())
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}
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};
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cx.field_imm(field.span, ident, subcall(field))
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}).collect::<Vec<_>>();
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if fields.is_empty() {
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// no fields, so construct like `None`
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cx.expr_ident(trait_span, ctor_ident)
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} else {
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cx.expr_struct_ident(trait_span, ctor_ident, fields)
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}
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}
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}
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