1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use ast::{MetaItem, Expr,};
14 use ext::base::{ExtCtxt, Annotatable};
15 use ext::build::AstBuilder;
16 use ext::deriving::generic::*;
17 use ext::deriving::generic::ty::*;
21 pub fn expand_deriving_show(cx: &mut ExtCtxt,
25 push: &mut FnMut(Annotatable))
27 // &mut ::std::fmt::Formatter
28 let fmtr = Ptr(Box::new(Literal(path_std!(cx, core::fmt::Formatter))),
29 Borrowed(None, ast::MutMutable));
31 let trait_def = TraitDef {
33 attributes: Vec::new(),
34 path: path_std!(cx, core::fmt::Debug),
35 additional_bounds: Vec::new(),
36 generics: LifetimeBounds::empty(),
40 generics: LifetimeBounds::empty(),
41 explicit_self: borrowed_explicit_self(),
43 ret_ty: Literal(path_std!(cx, core::fmt::Result)),
44 attributes: Vec::new(),
46 combine_substructure: combine_substructure(Box::new(|a, b, c| {
47 show_substructure(a, b, c)
51 associated_types: Vec::new(),
53 trait_def.expand(cx, mitem, item, push)
56 /// We use the debug builders to do the heavy lifting here
57 fn show_substructure(cx: &mut ExtCtxt, span: Span,
58 substr: &Substructure) -> P<Expr> {
59 // build fmt.debug_struct(<name>).field(<fieldname>, &<fieldval>)....build()
60 // or fmt.debug_tuple(<name>).field(&<fieldval>)....build()
61 // based on the "shape".
62 let ident = match *substr.fields {
63 Struct(_) => substr.type_ident,
64 EnumMatching(_, v, _) => v.node.name,
65 EnumNonMatchingCollapsed(..) | StaticStruct(..) | StaticEnum(..) => {
66 cx.span_bug(span, "nonsensical .fields in `#[derive(Debug)]`")
70 // We want to make sure we have the expn_id set so that we can use unstable methods
71 let span = Span { expn_id: cx.backtrace(), .. span };
72 let name = cx.expr_lit(span, ast::Lit_::LitStr(ident.name.as_str(),
73 ast::StrStyle::CookedStr));
74 let mut expr = substr.nonself_args[0].clone();
76 match *substr.fields {
77 Struct(ref fields) | EnumMatching(_, _, ref fields) => {
79 if fields.is_empty() || fields[0].name.is_none() {
80 // tuple struct/"normal" variant
81 expr = cx.expr_method_call(span,
83 token::str_to_ident("debug_tuple"),
87 // Use double indirection to make sure this works for unsized types
88 let field = cx.expr_addr_of(field.span, field.self_.clone());
89 let field = cx.expr_addr_of(field.span, field);
91 expr = cx.expr_method_call(span,
93 token::str_to_ident("field"),
97 // normal struct/struct variant
98 expr = cx.expr_method_call(span,
100 token::str_to_ident("debug_struct"),
103 for field in fields {
104 let name = cx.expr_lit(field.span, ast::Lit_::LitStr(
105 field.name.unwrap().name.as_str(),
106 ast::StrStyle::CookedStr));
108 // Use double indirection to make sure this works for unsized types
109 let field = cx.expr_addr_of(field.span, field.self_.clone());
110 let field = cx.expr_addr_of(field.span, field);
111 expr = cx.expr_method_call(span,
113 token::str_to_ident("field"),
121 cx.expr_method_call(span,
123 token::str_to_ident("finish"),