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huonwhuonw
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libsyntax: add #[deriving(Rand, ToStr)].
The former fills each field of a struct or enum variant with a random value (and picks a random enum variant). The latter makes the .to_str method have the same output as fmt!("%?", ..).
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‎src/libsyntax/ext/deriving/mod.rs

+6
Original file line numberDiff line numberDiff line change
@@ -23,6 +23,8 @@ pub mod clone;
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pub mod iter_bytes;
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pub mod encodable;
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pub mod decodable;
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pub mod rand;
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pub mod to_str;
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#[path="cmp/eq.rs"]
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pub mod eq;
@@ -86,6 +88,10 @@ pub fn expand_meta_deriving(cx: @ext_ctxt,
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~"Ord" => expand!(ord::expand_deriving_ord),
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~"TotalOrd" => expand!(totalord::expand_deriving_totalord),
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~"Rand" => expand!(rand::expand_deriving_rand),
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~"ToStr" => expand!(to_str::expand_deriving_to_str),
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tname => {
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cx.span_err(titem.span, fmt!("unknown \
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`deriving` trait: `%s`", tname));

‎src/libsyntax/ext/deriving/rand.rs

+136
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,136 @@
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// 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;
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use ast::{meta_item, item, expr, ident};
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use codemap::span;
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use ext::base::ext_ctxt;
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use ext::build;
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use ext::deriving::generic::*;
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pub fn expand_deriving_rand(cx: @ext_ctxt,
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span: span,
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mitem: @meta_item,
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in_items: ~[@item])
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-> ~[@item] {
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let trait_def = TraitDef {
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path: Path::new(~[~"core", ~"rand", ~"Rand"]),
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additional_bounds: ~[],
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generics: LifetimeBounds::empty(),
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methods: ~[
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MethodDef {
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name: ~"rand",
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generics: LifetimeBounds {
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lifetimes: ~[],
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bounds: ~[(~"R",
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~[ Path::new(~[~"core", ~"rand", ~"Rng"]) ])]
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},
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self_ty: None,
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args: ~[
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Ptr(~Literal(Path::new_local(~"R")),
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Borrowed(None, ast::m_imm))
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],
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ret_ty: Self,
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const_nonmatching: false,
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combine_substructure: rand_substructure
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}
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]
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};
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expand_deriving_generic(cx, span, mitem, in_items, &trait_def)
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}
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fn rand_substructure(cx: @ext_ctxt, span: span, substr: &Substructure) -> @expr {
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let rng = match substr.nonself_args {
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[rng] => ~[ rng ],
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_ => cx.bug("Incorrect number of arguments to `rand` in `deriving(Rand)`")
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};
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let rand_ident = ~[
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cx.ident_of(~"core"),
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cx.ident_of(~"rand"),
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cx.ident_of(~"Rand"),
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cx.ident_of(~"rand")
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];
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let rand_call = || {
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build::mk_call_global(cx, span,
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copy rand_ident, copy rng)
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};
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return match *substr.fields {
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StaticStruct(_, ref summary) => {
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rand_thing(cx, span, substr.type_ident, summary, rand_call)
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}
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StaticEnum(_, ref variants) => {
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if variants.is_empty() {
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cx.span_fatal(span, "`Rand` cannot be derived for enums with no variants");
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}
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let variant_count = build::mk_uint(cx, span, variants.len());
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// need to specify the uint-ness of the random number
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let u32_ty = build::mk_ty_path(cx, span, ~[cx.ident_of(~"uint")]);
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let r_ty = build::mk_ty_path(cx, span, ~[cx.ident_of(~"R")]);
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let rand_name = build::mk_raw_path_(span, copy rand_ident, None, ~[ u32_ty, r_ty ]);
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let rand_name = build::mk_path_raw(cx, span, rand_name);
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let rv_call = build::mk_call_(cx, span, rand_name, copy rng);
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// rand() % variants.len()
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let rand_variant = build::mk_binary(cx, span, ast::rem,
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rv_call, variant_count);
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let mut arms = do variants.mapi |i, id_sum| {
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let i_expr = build::mk_uint(cx, span, i);
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let pat = build::mk_pat_lit(cx, span, i_expr);
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match *id_sum {
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(ident, ref summary) => {
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build::mk_arm(cx, span,
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~[ pat ],
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rand_thing(cx, span, ident, summary, rand_call))
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}
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}
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};
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// _ => {} at the end. Should never occur
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arms.push(build::mk_unreachable_arm(cx, span));
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build::mk_expr(cx, span,
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ast::expr_match(rand_variant, arms))
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}
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_ => cx.bug("Non-static method in `deriving(Rand)`")
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};
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fn rand_thing(cx: @ext_ctxt, span: span,
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ctor_ident: ident,
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summary: &Either<uint, ~[ident]>,
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rand_call: &fn() -> @expr) -> @expr {
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let ctor_ident = ~[ ctor_ident ];
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match *summary {
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Left(copy count) => {
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if count == 0 {
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build::mk_path(cx, span, ctor_ident)
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} else {
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let exprs = vec::from_fn(count, |_| rand_call());
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build::mk_call(cx, span, ctor_ident, exprs)
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}
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}
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Right(ref fields) => {
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let rand_fields = do fields.map |ident| {
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build::Field {
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ident: *ident,
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ex: rand_call()
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}
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};
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build::mk_struct_e(cx, span, ctor_ident, rand_fields)
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}
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}
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}
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}

‎src/libsyntax/ext/deriving/to_str.rs

+54
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,54 @@
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// 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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11+
use ast::{meta_item, item, expr};
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use codemap::span;
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use ext::base::ext_ctxt;
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use ext::build;
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use ext::deriving::generic::*;
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pub fn expand_deriving_to_str(cx: @ext_ctxt,
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span: span,
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mitem: @meta_item,
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in_items: ~[@item])
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-> ~[@item] {
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let trait_def = TraitDef {
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path: Path::new(~[~"core", ~"to_str", ~"ToStr"]),
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additional_bounds: ~[],
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generics: LifetimeBounds::empty(),
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methods: ~[
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MethodDef {
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name: ~"to_str",
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generics: LifetimeBounds::empty(),
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self_ty: borrowed_explicit_self(),
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args: ~[],
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ret_ty: Ptr(~Literal(Path::new_local(~"str")), Owned),
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const_nonmatching: false,
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combine_substructure: to_str_substructure
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}
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]
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};
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expand_deriving_generic(cx, span, mitem, in_items, &trait_def)
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}
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fn to_str_substructure(cx: @ext_ctxt, span: span, substr: &Substructure) -> @expr {
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match substr.self_args {
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[self_obj] => {
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let self_addr = build::mk_addr_of(cx, span, self_obj);
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build::mk_call_global(cx, span,
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~[cx.ident_of(~"core"),
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cx.ident_of(~"sys"),
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cx.ident_of(~"log_str")],
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~[self_addr])
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}
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_ => cx.span_bug(span, ~"Invalid number of arguments in `deriving(ToStr)`")
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}
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}

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