src/libsyntax_ext/deriving/generic/ty.rs

   1 // Copyright 2013 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 //! A mini version of ast::Ty, which is easier to use, and features an explicit `Self` type to use
  12 //! when specifying impls to be derived.
  13
  14 pub use self::PtrTy::*;
  15 pub use self::Ty::*;
  16
  17 use syntax::ast;
  18 use syntax::ast::{Expr,Generics,Ident};
  19 use syntax::ext::base::ExtCtxt;
  20 use syntax::ext::build::AstBuilder;
  21 use syntax::codemap::{Span,respan};
  22 use syntax::parse::token::special_idents;
  23 use syntax::ptr::P;
  24
  25 /// The types of pointers
  26 #[derive(Clone, Eq, PartialEq)]
  27 #[allow(dead_code)]
  28 pub enum PtrTy<'a> {
  29     /// &'lifetime mut
  30     Borrowed(Option<&'a str>, ast::Mutability),
  31     /// *mut
  32     Raw(ast::Mutability),
  33 }
  34
  35 /// A path, e.g. `::std::option::Option::<i32>` (global). Has support
  36 /// for type parameters and a lifetime.
  37 #[derive(Clone, Eq, PartialEq)]
  38 pub struct Path<'a> {
  39     pub path: Vec<&'a str> ,
  40     pub lifetime: Option<&'a str>,
  41     pub params: Vec<Box<Ty<'a>>>,
  42     pub global: bool,
  43 }
  44
  45 impl<'a> Path<'a> {
  46     pub fn new<'r>(path: Vec<&'r str> ) -> Path<'r> {
  47         Path::new_(path, None, Vec::new(), true)
  48     }
  49     pub fn new_local<'r>(path: &'r str) -> Path<'r> {
  50         Path::new_(vec!( path ), None, Vec::new(), false)
  51     }
  52     pub fn new_<'r>(path: Vec<&'r str> ,
  53                     lifetime: Option<&'r str>,
  54                     params: Vec<Box<Ty<'r>>>,
  55                     global: bool)
  56                     -> Path<'r> {
  57         Path {
  58             path: path,
  59             lifetime: lifetime,
  60             params: params,
  61             global: global
  62         }
  63     }
  64
  65     pub fn to_ty(&self,
  66                  cx: &ExtCtxt,
  67                  span: Span,
  68                  self_ty: Ident,
  69                  self_generics: &Generics)
  70                  -> P<ast::Ty> {
  71         cx.ty_path(self.to_path(cx, span, self_ty, self_generics))
  72     }
  73     pub fn to_path(&self,
  74                    cx: &ExtCtxt,
  75                    span: Span,
  76                    self_ty: Ident,
  77                    self_generics: &Generics)
  78                    -> ast::Path {
  79         let idents = self.path.iter().map(|s| cx.ident_of(*s)).collect();
  80         let lt = mk_lifetimes(cx, span, &self.lifetime);
  81         let tys = self.params.iter().map(|t| t.to_ty(cx, span, self_ty, self_generics)).collect();
  82
  83         cx.path_all(span, self.global, idents, lt, tys, Vec::new())
  84     }
  85 }
  86
  87 /// A type. Supports pointers, Self, and literals
  88 #[derive(Clone, Eq, PartialEq)]
  89 pub enum Ty<'a> {
  90     Self_,
  91     /// &/Box/ Ty
  92     Ptr(Box<Ty<'a>>, PtrTy<'a>),
  93     /// mod::mod::Type<[lifetime], [Params...]>, including a plain type
  94     /// parameter, and things like `i32`
  95     Literal(Path<'a>),
  96     /// includes unit
  97     Tuple(Vec<Ty<'a>> )
  98 }
  99
 100 pub fn borrowed_ptrty<'r>() -> PtrTy<'r> {
 101     Borrowed(None, ast::MutImmutable)
 102 }
 103 pub fn borrowed<'r>(ty: Box<Ty<'r>>) -> Ty<'r> {
 104     Ptr(ty, borrowed_ptrty())
 105 }
 106
 107 pub fn borrowed_explicit_self<'r>() -> Option<Option<PtrTy<'r>>> {
 108     Some(Some(borrowed_ptrty()))
 109 }
 110
 111 pub fn borrowed_self<'r>() -> Ty<'r> {
 112     borrowed(Box::new(Self_))
 113 }
 114
 115 pub fn nil_ty<'r>() -> Ty<'r> {
 116     Tuple(Vec::new())
 117 }
 118
 119 fn mk_lifetime(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Option<ast::Lifetime> {
 120     match *lt {
 121         Some(ref s) => Some(cx.lifetime(span, cx.ident_of(*s).name)),
 122         None => None
 123     }
 124 }
 125
 126 fn mk_lifetimes(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Vec<ast::Lifetime> {
 127     match *lt {
 128         Some(ref s) => vec!(cx.lifetime(span, cx.ident_of(*s).name)),
 129         None => vec!()
 130     }
 131 }
 132
 133 impl<'a> Ty<'a> {
 134     pub fn to_ty(&self,
 135                  cx: &ExtCtxt,
 136                  span: Span,
 137                  self_ty: Ident,
 138                  self_generics: &Generics)
 139                  -> P<ast::Ty> {
 140         match *self {
 141             Ptr(ref ty, ref ptr) => {
 142                 let raw_ty = ty.to_ty(cx, span, self_ty, self_generics);
 143                 match *ptr {
 144                     Borrowed(ref lt, mutbl) => {
 145                         let lt = mk_lifetime(cx, span, lt);
 146                         cx.ty_rptr(span, raw_ty, lt, mutbl)
 147                     }
 148                     Raw(mutbl) => cx.ty_ptr(span, raw_ty, mutbl)
 149                 }
 150             }
 151             Literal(ref p) => { p.to_ty(cx, span, self_ty, self_generics) }
 152             Self_  => {
 153                 cx.ty_path(self.to_path(cx, span, self_ty, self_generics))
 154             }
 155             Tuple(ref fields) => {
 156                 let ty = ast::TyTup(fields.iter()
 157                     .map(|f| f.to_ty(cx, span, self_ty, self_generics))
 158                     .collect());
 159                 cx.ty(span, ty)
 160             }
 161         }
 162     }
 163
 164     pub fn to_path(&self,
 165                    cx: &ExtCtxt,
 166                    span: Span,
 167                    self_ty: Ident,
 168                    self_generics: &Generics)
 169                    -> ast::Path {
 170         match *self {
 171             Self_ => {
 172                 let self_params = self_generics.ty_params.map(|ty_param| {
 173                     cx.ty_ident(span, ty_param.ident)
 174                 });
 175                 let lifetimes = self_generics.lifetimes.iter()
 176                                                        .map(|d| d.lifetime)
 177                                                        .collect();
 178
 179                 cx.path_all(span, false, vec!(self_ty), lifetimes,
 180                             self_params.into_vec(), Vec::new())
 181             }
 182             Literal(ref p) => {
 183                 p.to_path(cx, span, self_ty, self_generics)
 184             }
 185             Ptr(..) => { cx.span_bug(span, "pointer in a path in generic `derive`") }
 186             Tuple(..) => { cx.span_bug(span, "tuple in a path in generic `derive`") }
 187         }
 188     }
 189 }
 190
 191
 192 fn mk_ty_param(cx: &ExtCtxt,
 193                span: Span,
 194                name: &str,
 195                bounds: &[Path],
 196                self_ident: Ident,
 197                self_generics: &Generics)
 198                -> ast::TyParam {
 199     let bounds =
 200         bounds.iter().map(|b| {
 201             let path = b.to_path(cx, span, self_ident, self_generics);
 202             cx.typarambound(path)
 203         }).collect();
 204     cx.typaram(span, cx.ident_of(name), bounds, None)
 205 }
 206
 207 fn mk_generics(lifetimes: Vec<ast::LifetimeDef>, ty_params: Vec<ast::TyParam>)
 208                -> Generics {
 209     Generics {
 210         lifetimes: lifetimes,
 211         ty_params: P::from_vec(ty_params),
 212         where_clause: ast::WhereClause {
 213             id: ast::DUMMY_NODE_ID,
 214             predicates: Vec::new(),
 215         },
 216     }
 217 }
 218
 219 /// Lifetimes and bounds on type parameters
 220 #[derive(Clone)]
 221 pub struct LifetimeBounds<'a> {
 222     pub lifetimes: Vec<(&'a str, Vec<&'a str>)>,
 223     pub bounds: Vec<(&'a str, Vec<Path<'a>>)>,
 224 }
 225
 226 impl<'a> LifetimeBounds<'a> {
 227     pub fn empty() -> LifetimeBounds<'a> {
 228         LifetimeBounds {
 229             lifetimes: Vec::new(), bounds: Vec::new()
 230         }
 231     }
 232     pub fn to_generics(&self,
 233                        cx: &ExtCtxt,
 234                        span: Span,
 235                        self_ty: Ident,
 236                        self_generics: &Generics)
 237                        -> Generics {
 238         let lifetimes = self.lifetimes.iter().map(|&(ref lt, ref bounds)| {
 239             let bounds =
 240                 bounds.iter().map(
 241                     |b| cx.lifetime(span, cx.ident_of(*b).name)).collect();
 242             cx.lifetime_def(span, cx.ident_of(*lt).name, bounds)
 243         }).collect();
 244         let ty_params = self.bounds.iter().map(|t| {
 245             match *t {
 246                 (ref name, ref bounds) => {
 247                     mk_ty_param(cx,
 248                                 span,
 249                                 *name,
 250                                 bounds,
 251                                 self_ty,
 252                                 self_generics)
 253                 }
 254             }
 255         }).collect();
 256         mk_generics(lifetimes, ty_params)
 257     }
 258 }
 259
 260 pub fn get_explicit_self(cx: &ExtCtxt, span: Span, self_ptr: &Option<PtrTy>)
 261     -> (P<Expr>, ast::ExplicitSelf) {
 262     // this constructs a fresh `self` path, which will match the fresh `self` binding
 263     // created below.
 264     let self_path = cx.expr_self(span);
 265     match *self_ptr {
 266         None => {
 267             (self_path, respan(span, ast::SelfValue(special_idents::self_)))
 268         }
 269         Some(ref ptr) => {
 270             let self_ty = respan(
 271                 span,
 272                 match *ptr {
 273                     Borrowed(ref lt, mutbl) => {
 274                         let lt = lt.map(|s| cx.lifetime(span, cx.ident_of(s).name));
 275                         ast::SelfRegion(lt, mutbl, special_idents::self_)
 276                     }
 277                     Raw(_) => cx.span_bug(span, "attempted to use *self in deriving definition")
 278                 });
 279             let self_expr = cx.expr_deref(span, self_path);
 280             (self_expr, self_ty)
 281         }
 282     }
 283 }