| // Copyright 2015 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. |
| |
| // force-host |
| |
| #![feature(plugin_registrar)] |
| #![feature(box_syntax)] |
| #![feature(rustc_private)] |
| |
| extern crate syntax; |
| extern crate syntax_ext; |
| extern crate rustc; |
| extern crate rustc_plugin; |
| |
| use syntax::ast; |
| use syntax::attr::AttrMetaMethods; |
| use syntax::codemap::Span; |
| use syntax::ext::base::{MultiDecorator, ExtCtxt, Annotatable}; |
| use syntax::ext::build::AstBuilder; |
| use syntax::parse::token; |
| use syntax::ptr::P; |
| use syntax_ext::deriving::generic::{cs_fold, TraitDef, MethodDef, combine_substructure}; |
| use syntax_ext::deriving::generic::{Substructure, Struct, EnumMatching}; |
| use syntax_ext::deriving::generic::ty::{Literal, LifetimeBounds, Path, borrowed_explicit_self}; |
| use rustc_plugin::Registry; |
| |
| #[plugin_registrar] |
| pub fn plugin_registrar(reg: &mut Registry) { |
| reg.register_syntax_extension( |
| token::intern("derive_TotalSum"), |
| MultiDecorator(box expand)); |
| } |
| |
| fn expand(cx: &mut ExtCtxt, |
| span: Span, |
| mitem: &ast::MetaItem, |
| item: &Annotatable, |
| push: &mut FnMut(Annotatable)) { |
| let trait_def = TraitDef { |
| span: span, |
| attributes: vec![], |
| path: Path::new(vec!["TotalSum"]), |
| additional_bounds: vec![], |
| generics: LifetimeBounds::empty(), |
| associated_types: vec![], |
| is_unsafe: false, |
| methods: vec![ |
| MethodDef { |
| name: "total_sum", |
| generics: LifetimeBounds::empty(), |
| explicit_self: borrowed_explicit_self(), |
| args: vec![], |
| ret_ty: Literal(Path::new_local("isize")), |
| attributes: vec![], |
| is_unsafe: false, |
| combine_substructure: combine_substructure(Box::new(totalsum_substructure)), |
| }, |
| ], |
| }; |
| |
| trait_def.expand(cx, mitem, item, push) |
| } |
| |
| // Mostly copied from syntax::ext::deriving::hash |
| /// Defines how the implementation for `trace()` is to be generated |
| fn totalsum_substructure(cx: &mut ExtCtxt, trait_span: Span, |
| substr: &Substructure) -> P<ast::Expr> { |
| let fields = match *substr.fields { |
| Struct(ref fs) | EnumMatching(_, _, ref fs) => fs, |
| _ => cx.span_bug(trait_span, "impossible substructure") |
| }; |
| |
| fields.iter().fold(cx.expr_isize(trait_span, 0), |acc, ref item| { |
| if item.attrs.iter().find(|a| a.check_name("ignore")).is_some() { |
| acc |
| } else { |
| cx.expr_binary(item.span, ast::BiAdd, acc, |
| cx.expr_method_call(item.span, |
| item.self_.clone(), |
| substr.method_ident, |
| Vec::new())) |
| } |
| }) |
| } |