src/libsyntax_ext/deriving/mod.rs

   1 // Copyright 2012-2015 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.
   4 //
   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.
  10
  11 //! The compiler code necessary to implement the `#[derive]` extensions.
  12
  13 use std::rc::Rc;
  14 use syntax::ast;
  15 use syntax::ext::base::{Annotatable, ExtCtxt, SyntaxExtension, Resolver};
  16 use syntax::ext::build::AstBuilder;
  17 use syntax::ext::hygiene::{Mark, SyntaxContext};
  18 use syntax::ptr::P;
  19 use syntax::symbol::Symbol;
  20 use syntax_pos::Span;
  21
  22 macro_rules! pathvec {
  23     ($($x:ident)::+) => (
  24         vec![ $( stringify!($x) ),+ ]
  25     )
  26 }
  27
  28 macro_rules! path_local {
  29     ($x:ident) => (
  30         ::deriving::generic::ty::Path::new_local(stringify!($x))
  31     )
  32 }
  33
  34 macro_rules! pathvec_std {
  35     ($cx:expr, $first:ident :: $($rest:ident)::+) => ({
  36         let mut v = pathvec![$($rest)::+];
  37         if let Some(s) = $cx.crate_root {
  38             v.insert(0, s);
  39         }
  40         v
  41     })
  42 }
  43
  44 macro_rules! path_std {
  45     ($($x:tt)*) => (
  46         ::deriving::generic::ty::Path::new( pathvec_std!( $($x)* ) )
  47     )
  48 }
  49
  50 pub mod bounds;
  51 pub mod clone;
  52 pub mod encodable;
  53 pub mod decodable;
  54 pub mod hash;
  55 pub mod debug;
  56 pub mod default;
  57 pub mod custom;
  58
  59 #[path="cmp/partial_eq.rs"]
  60 pub mod partial_eq;
  61 #[path="cmp/eq.rs"]
  62 pub mod eq;
  63 #[path="cmp/partial_ord.rs"]
  64 pub mod partial_ord;
  65 #[path="cmp/ord.rs"]
  66 pub mod ord;
  67
  68
  69 pub mod generic;
  70
  71 macro_rules! derive_traits {
  72     ($( $name:expr => $func:path, )+) => {
  73         pub fn is_builtin_trait(name: ast::Name) -> bool {
  74             match &*name.as_str() {
  75                 $( $name )|+ => true,
  76                 _ => false,
  77             }
  78         }
  79
  80         pub fn register_builtin_derives(resolver: &mut Resolver) {
  81             $(
  82                 resolver.add_builtin(
  83                     ast::Ident::with_empty_ctxt(Symbol::intern($name)),
  84                     Rc::new(SyntaxExtension::BuiltinDerive($func))
  85                 );
  86             )*
  87         }
  88     }
  89 }
  90
  91 derive_traits! {
  92     "Clone" => clone::expand_deriving_clone,
  93
  94     "Hash" => hash::expand_deriving_hash,
  95
  96     "RustcEncodable" => encodable::expand_deriving_rustc_encodable,
  97
  98     "RustcDecodable" => decodable::expand_deriving_rustc_decodable,
  99
 100     "PartialEq" => partial_eq::expand_deriving_partial_eq,
 101     "Eq" => eq::expand_deriving_eq,
 102     "PartialOrd" => partial_ord::expand_deriving_partial_ord,
 103     "Ord" => ord::expand_deriving_ord,
 104
 105     "Debug" => debug::expand_deriving_debug,
 106
 107     "Default" => default::expand_deriving_default,
 108
 109     "Send" => bounds::expand_deriving_unsafe_bound,
 110     "Sync" => bounds::expand_deriving_unsafe_bound,
 111     "Copy" => bounds::expand_deriving_copy,
 112
 113     // deprecated
 114     "Encodable" => encodable::expand_deriving_encodable,
 115     "Decodable" => decodable::expand_deriving_decodable,
 116 }
 117
 118 #[inline] // because `name` is a compile-time constant
 119 fn warn_if_deprecated(ecx: &mut ExtCtxt, sp: Span, name: &str) {
 120     if let Some(replacement) = match name {
 121         "Encodable" => Some("RustcEncodable"),
 122         "Decodable" => Some("RustcDecodable"),
 123         _ => None,
 124     } {
 125         ecx.span_warn(sp,
 126                       &format!("derive({}) is deprecated in favor of derive({})",
 127                                name,
 128                                replacement));
 129     }
 130 }
 131
 132 /// Construct a name for the inner type parameter that can't collide with any type parameters of
 133 /// the item. This is achieved by starting with a base and then concatenating the names of all
 134 /// other type parameters.
 135 // FIXME(aburka): use real hygiene when that becomes possible
 136 fn hygienic_type_parameter(item: &Annotatable, base: &str) -> String {
 137     let mut typaram = String::from(base);
 138     if let Annotatable::Item(ref item) = *item {
 139         match item.node {
 140             ast::ItemKind::Struct(_, ast::Generics { ref ty_params, .. }) |
 141             ast::ItemKind::Enum(_, ast::Generics { ref ty_params, .. }) => {
 142                 for ty in ty_params.iter() {
 143                     typaram.push_str(&ty.ident.name.as_str());
 144                 }
 145             }
 146
 147             _ => {}
 148         }
 149     }
 150
 151     typaram
 152 }
 153
 154 /// Constructs an expression that calls an intrinsic
 155 fn call_intrinsic(cx: &ExtCtxt,
 156                   mut span: Span,
 157                   intrinsic: &str,
 158                   args: Vec<P<ast::Expr>>)
 159                   -> P<ast::Expr> {
 160     if cx.current_expansion.mark.expn_info().unwrap().callee.allow_internal_unstable {
 161         span.ctxt = cx.backtrace();
 162     } else { // Avoid instability errors with user defined curstom derives, cc #36316
 163         let mut info = cx.current_expansion.mark.expn_info().unwrap();
 164         info.callee.allow_internal_unstable = true;
 165         let mark = Mark::fresh(Mark::root());
 166         mark.set_expn_info(info);
 167         span.ctxt = SyntaxContext::empty().apply_mark(mark);
 168     }
 169     let path = cx.std_path(&["intrinsics", intrinsic]);
 170     let call = cx.expr_call_global(span, path, args);
 171
 172     cx.expr_block(P(ast::Block {
 173         stmts: vec![cx.stmt_expr(call)],
 174         id: ast::DUMMY_NODE_ID,
 175         rules: ast::BlockCheckMode::Unsafe(ast::CompilerGenerated),
 176         span: span,
 177     }))
 178 }