src/libsyntax/ext/build.rs

   1 // Copyright 2012 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 use abi;
  12 use ast::{P, Ident, Generics, NodeId, Expr};
  13 use ast;
  14 use ast_util;
  15 use attr;
  16 use codemap::{Span, respan, Spanned, DUMMY_SP, Pos};
  17 use ext::base::ExtCtxt;
  18 use fold::Folder;
  19 use owned_slice::OwnedSlice;
  20 use parse::token::special_idents;
  21 use parse::token::InternedString;
  22 use parse::token;
  23
  24 use std::gc::{Gc, GC};
  25
  26 // Transitional reexports so qquote can find the paths it is looking for
  27 mod syntax {
  28     pub use ext;
  29     pub use parse;
  30 }
  31
  32 pub trait AstBuilder {
  33     // paths
  34     fn path(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path;
  35     fn path_ident(&self, span: Span, id: ast::Ident) -> ast::Path;
  36     fn path_global(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path;
  37     fn path_all(&self, sp: Span,
  38                 global: bool,
  39                 idents: Vec<ast::Ident> ,
  40                 lifetimes: Vec<ast::Lifetime>,
  41                 types: Vec<P<ast::Ty>> )
  42         -> ast::Path;
  43
  44     // types
  45     fn ty_mt(&self, ty: P<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy;
  46
  47     fn ty(&self, span: Span, ty: ast::Ty_) -> P<ast::Ty>;
  48     fn ty_path(&self, ast::Path, Option<OwnedSlice<ast::TyParamBound>>) -> P<ast::Ty>;
  49     fn ty_ident(&self, span: Span, idents: ast::Ident) -> P<ast::Ty>;
  50
  51     fn ty_rptr(&self, span: Span,
  52                ty: P<ast::Ty>,
  53                lifetime: Option<ast::Lifetime>,
  54                mutbl: ast::Mutability) -> P<ast::Ty>;
  55     fn ty_ptr(&self, span: Span,
  56               ty: P<ast::Ty>,
  57               mutbl: ast::Mutability) -> P<ast::Ty>;
  58     fn ty_uniq(&self, span: Span, ty: P<ast::Ty>) -> P<ast::Ty>;
  59
  60     fn ty_option(&self, ty: P<ast::Ty>) -> P<ast::Ty>;
  61     fn ty_infer(&self, sp: Span) -> P<ast::Ty>;
  62     fn ty_nil(&self) -> P<ast::Ty>;
  63
  64     fn ty_vars(&self, ty_params: &OwnedSlice<ast::TyParam>) -> Vec<P<ast::Ty>> ;
  65     fn ty_vars_global(&self, ty_params: &OwnedSlice<ast::TyParam>) -> Vec<P<ast::Ty>> ;
  66     fn ty_field_imm(&self, span: Span, name: Ident, ty: P<ast::Ty>) -> ast::TypeField;
  67     fn strip_bounds(&self, bounds: &Generics) -> Generics;
  68
  69     fn typaram(&self,
  70                span: Span,
  71                id: ast::Ident,
  72                bounds: OwnedSlice<ast::TyParamBound>,
  73                unbound: Option<ast::TyParamBound>,
  74                default: Option<P<ast::Ty>>) -> ast::TyParam;
  75
  76     fn trait_ref(&self, path: ast::Path) -> ast::TraitRef;
  77     fn typarambound(&self, path: ast::Path) -> ast::TyParamBound;
  78     fn lifetime(&self, span: Span, ident: ast::Name) -> ast::Lifetime;
  79     fn lifetime_def(&self,
  80                     span: Span,
  81                     name: ast::Name,
  82                     bounds: Vec<ast::Lifetime>)
  83                     -> ast::LifetimeDef;
  84
  85     // statements
  86     fn stmt_expr(&self, expr: Gc<ast::Expr>) -> Gc<ast::Stmt>;
  87     fn stmt_let(&self, sp: Span, mutbl: bool, ident: ast::Ident,
  88                 ex: Gc<ast::Expr>) -> Gc<ast::Stmt>;
  89     fn stmt_let_typed(&self,
  90                       sp: Span,
  91                       mutbl: bool,
  92                       ident: ast::Ident,
  93                       typ: P<ast::Ty>,
  94                       ex: Gc<ast::Expr>)
  95                       -> Gc<ast::Stmt>;
  96     fn stmt_item(&self, sp: Span, item: Gc<ast::Item>) -> Gc<ast::Stmt>;
  97
  98     // blocks
  99     fn block(&self, span: Span, stmts: Vec<Gc<ast::Stmt>>,
 100              expr: Option<Gc<ast::Expr>>) -> P<ast::Block>;
 101     fn block_expr(&self, expr: Gc<ast::Expr>) -> P<ast::Block>;
 102     fn block_all(&self, span: Span,
 103                  view_items: Vec<ast::ViewItem> ,
 104                  stmts: Vec<Gc<ast::Stmt>> ,
 105                  expr: Option<Gc<ast::Expr>>) -> P<ast::Block>;
 106
 107     // expressions
 108     fn expr(&self, span: Span, node: ast::Expr_) -> Gc<ast::Expr>;
 109     fn expr_path(&self, path: ast::Path) -> Gc<ast::Expr>;
 110     fn expr_ident(&self, span: Span, id: ast::Ident) -> Gc<ast::Expr>;
 111
 112     fn expr_self(&self, span: Span) -> Gc<ast::Expr>;
 113     fn expr_binary(&self, sp: Span, op: ast::BinOp,
 114                    lhs: Gc<ast::Expr>, rhs: Gc<ast::Expr>) -> Gc<ast::Expr>;
 115     fn expr_deref(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr>;
 116     fn expr_unary(&self, sp: Span, op: ast::UnOp, e: Gc<ast::Expr>) -> Gc<ast::Expr>;
 117
 118     fn expr_managed(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr>;
 119     fn expr_addr_of(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr>;
 120     fn expr_mut_addr_of(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr>;
 121     fn expr_field_access(&self, span: Span, expr: Gc<ast::Expr>,
 122                          ident: ast::Ident) -> Gc<ast::Expr>;
 123     fn expr_call(&self, span: Span, expr: Gc<ast::Expr>,
 124                  args: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr>;
 125     fn expr_call_ident(&self, span: Span, id: ast::Ident,
 126                        args: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr>;
 127     fn expr_call_global(&self, sp: Span, fn_path: Vec<ast::Ident> ,
 128                         args: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr>;
 129     fn expr_method_call(&self, span: Span,
 130                         expr: Gc<ast::Expr>, ident: ast::Ident,
 131                         args: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr>;
 132     fn expr_block(&self, b: P<ast::Block>) -> Gc<ast::Expr>;
 133     fn expr_cast(&self, sp: Span, expr: Gc<ast::Expr>,
 134                  ty: P<ast::Ty>) -> Gc<ast::Expr>;
 135
 136     fn field_imm(&self, span: Span, name: Ident, e: Gc<ast::Expr>) -> ast::Field;
 137     fn expr_struct(&self, span: Span, path: ast::Path,
 138                    fields: Vec<ast::Field> ) -> Gc<ast::Expr>;
 139     fn expr_struct_ident(&self, span: Span, id: ast::Ident,
 140                          fields: Vec<ast::Field> ) -> Gc<ast::Expr>;
 141
 142     fn expr_lit(&self, sp: Span, lit: ast::Lit_) -> Gc<ast::Expr>;
 143
 144     fn expr_uint(&self, span: Span, i: uint) -> Gc<ast::Expr>;
 145     fn expr_int(&self, sp: Span, i: int) -> Gc<ast::Expr>;
 146     fn expr_u8(&self, sp: Span, u: u8) -> Gc<ast::Expr>;
 147     fn expr_bool(&self, sp: Span, value: bool) -> Gc<ast::Expr>;
 148
 149     fn expr_vec(&self, sp: Span, exprs: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr>;
 150     fn expr_vec_ng(&self, sp: Span) -> Gc<ast::Expr>;
 151     fn expr_vec_slice(&self, sp: Span, exprs: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr>;
 152     fn expr_str(&self, sp: Span, s: InternedString) -> Gc<ast::Expr>;
 153
 154     fn expr_some(&self, sp: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr>;
 155     fn expr_none(&self, sp: Span) -> Gc<ast::Expr>;
 156
 157     fn expr_tuple(&self, sp: Span, exprs: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr>;
 158
 159     fn expr_fail(&self, span: Span, msg: InternedString) -> Gc<ast::Expr>;
 160     fn expr_unreachable(&self, span: Span) -> Gc<ast::Expr>;
 161
 162     fn expr_ok(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr>;
 163     fn expr_err(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr>;
 164     fn expr_try(&self, span: Span, head: Gc<ast::Expr>) -> Gc<ast::Expr>;
 165
 166     fn pat(&self, span: Span, pat: ast::Pat_) -> Gc<ast::Pat>;
 167     fn pat_wild(&self, span: Span) -> Gc<ast::Pat>;
 168     fn pat_lit(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Pat>;
 169     fn pat_ident(&self, span: Span, ident: ast::Ident) -> Gc<ast::Pat>;
 170
 171     fn pat_ident_binding_mode(&self,
 172                               span: Span,
 173                               ident: ast::Ident,
 174                               bm: ast::BindingMode) -> Gc<ast::Pat>;
 175     fn pat_enum(&self, span: Span, path: ast::Path,
 176                 subpats: Vec<Gc<ast::Pat>>) -> Gc<ast::Pat>;
 177     fn pat_struct(&self, span: Span,
 178                   path: ast::Path, field_pats: Vec<ast::FieldPat> ) -> Gc<ast::Pat>;
 179     fn pat_tuple(&self, span: Span, pats: Vec<Gc<ast::Pat>>) -> Gc<ast::Pat>;
 180
 181     fn pat_some(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat>;
 182     fn pat_none(&self, span: Span) -> Gc<ast::Pat>;
 183
 184     fn pat_ok(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat>;
 185     fn pat_err(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat>;
 186
 187     fn arm(&self, span: Span, pats: Vec<Gc<ast::Pat>> , expr: Gc<ast::Expr>) -> ast::Arm;
 188     fn arm_unreachable(&self, span: Span) -> ast::Arm;
 189
 190     fn expr_match(&self, span: Span, arg: Gc<ast::Expr>, arms: Vec<ast::Arm> ) -> Gc<ast::Expr>;
 191     fn expr_if(&self, span: Span,
 192                cond: Gc<ast::Expr>, then: Gc<ast::Expr>,
 193                els: Option<Gc<ast::Expr>>) -> Gc<ast::Expr>;
 194     fn expr_loop(&self, span: Span, block: P<ast::Block>) -> Gc<ast::Expr>;
 195
 196     fn lambda_fn_decl(&self, span: Span,
 197                       fn_decl: P<ast::FnDecl>, blk: P<ast::Block>) -> Gc<ast::Expr>;
 198
 199     fn lambda(&self, span: Span, ids: Vec<ast::Ident> , blk: P<ast::Block>) -> Gc<ast::Expr>;
 200     fn lambda0(&self, span: Span, blk: P<ast::Block>) -> Gc<ast::Expr>;
 201     fn lambda1(&self, span: Span, blk: P<ast::Block>, ident: ast::Ident) -> Gc<ast::Expr>;
 202
 203     fn lambda_expr(&self, span: Span, ids: Vec<ast::Ident> , blk: Gc<ast::Expr>) -> Gc<ast::Expr>;
 204     fn lambda_expr_0(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr>;
 205     fn lambda_expr_1(&self, span: Span, expr: Gc<ast::Expr>, ident: ast::Ident) -> Gc<ast::Expr>;
 206
 207     fn lambda_stmts(&self, span: Span, ids: Vec<ast::Ident>,
 208                     blk: Vec<Gc<ast::Stmt>>) -> Gc<ast::Expr>;
 209     fn lambda_stmts_0(&self, span: Span,
 210                       stmts: Vec<Gc<ast::Stmt>>) -> Gc<ast::Expr>;
 211     fn lambda_stmts_1(&self, span: Span,
 212                       stmts: Vec<Gc<ast::Stmt>>, ident: ast::Ident) -> Gc<ast::Expr>;
 213
 214     // items
 215     fn item(&self, span: Span,
 216             name: Ident, attrs: Vec<ast::Attribute>,
 217             node: ast::Item_) -> Gc<ast::Item>;
 218
 219     fn arg(&self, span: Span, name: Ident, ty: P<ast::Ty>) -> ast::Arg;
 220     // FIXME unused self
 221     fn fn_decl(&self, inputs: Vec<ast::Arg> , output: P<ast::Ty>) -> P<ast::FnDecl>;
 222
 223     fn item_fn_poly(&self,
 224                     span: Span,
 225                     name: Ident,
 226                     inputs: Vec<ast::Arg> ,
 227                     output: P<ast::Ty>,
 228                     generics: Generics,
 229                     body: P<ast::Block>) -> Gc<ast::Item>;
 230     fn item_fn(&self,
 231                span: Span,
 232                name: Ident,
 233                inputs: Vec<ast::Arg> ,
 234                output: P<ast::Ty>,
 235                body: P<ast::Block>) -> Gc<ast::Item>;
 236
 237     fn variant(&self, span: Span, name: Ident, tys: Vec<P<ast::Ty>> ) -> ast::Variant;
 238     fn item_enum_poly(&self,
 239                       span: Span,
 240                       name: Ident,
 241                       enum_definition: ast::EnumDef,
 242                       generics: Generics) -> Gc<ast::Item>;
 243     fn item_enum(&self, span: Span, name: Ident,
 244                  enum_def: ast::EnumDef) -> Gc<ast::Item>;
 245
 246     fn item_struct_poly(&self,
 247                         span: Span,
 248                         name: Ident,
 249                         struct_def: ast::StructDef,
 250                         generics: Generics) -> Gc<ast::Item>;
 251     fn item_struct(&self, span: Span, name: Ident,
 252                    struct_def: ast::StructDef) -> Gc<ast::Item>;
 253
 254     fn item_mod(&self, span: Span, inner_span: Span,
 255                 name: Ident, attrs: Vec<ast::Attribute>,
 256                 vi: Vec<ast::ViewItem>,
 257                 items: Vec<Gc<ast::Item>>) -> Gc<ast::Item>;
 258
 259     fn item_static(&self,
 260                    span: Span,
 261                    name: Ident,
 262                    ty: P<ast::Ty>,
 263                    mutbl: ast::Mutability,
 264                    expr: Gc<ast::Expr>)
 265                    -> Gc<ast::Item>;
 266
 267     fn item_ty_poly(&self,
 268                     span: Span,
 269                     name: Ident,
 270                     ty: P<ast::Ty>,
 271                     generics: Generics) -> Gc<ast::Item>;
 272     fn item_ty(&self, span: Span, name: Ident, ty: P<ast::Ty>) -> Gc<ast::Item>;
 273
 274     fn attribute(&self, sp: Span, mi: Gc<ast::MetaItem>) -> ast::Attribute;
 275
 276     fn meta_word(&self, sp: Span, w: InternedString) -> Gc<ast::MetaItem>;
 277     fn meta_list(&self,
 278                  sp: Span,
 279                  name: InternedString,
 280                  mis: Vec<Gc<ast::MetaItem>>)
 281                  -> Gc<ast::MetaItem>;
 282     fn meta_name_value(&self,
 283                        sp: Span,
 284                        name: InternedString,
 285                        value: ast::Lit_)
 286                        -> Gc<ast::MetaItem>;
 287
 288     fn view_use(&self, sp: Span,
 289                 vis: ast::Visibility, vp: Gc<ast::ViewPath>) -> ast::ViewItem;
 290     fn view_use_simple(&self, sp: Span, vis: ast::Visibility, path: ast::Path) -> ast::ViewItem;
 291     fn view_use_simple_(&self, sp: Span, vis: ast::Visibility,
 292                         ident: ast::Ident, path: ast::Path) -> ast::ViewItem;
 293     fn view_use_list(&self, sp: Span, vis: ast::Visibility,
 294                      path: Vec<ast::Ident> , imports: &[ast::Ident]) -> ast::ViewItem;
 295     fn view_use_glob(&self, sp: Span,
 296                      vis: ast::Visibility, path: Vec<ast::Ident> ) -> ast::ViewItem;
 297 }
 298
 299 impl<'a> AstBuilder for ExtCtxt<'a> {
 300     fn path(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path {
 301         self.path_all(span, false, strs, Vec::new(), Vec::new())
 302     }
 303     fn path_ident(&self, span: Span, id: ast::Ident) -> ast::Path {
 304         self.path(span, vec!(id))
 305     }
 306     fn path_global(&self, span: Span, strs: Vec<ast::Ident> ) -> ast::Path {
 307         self.path_all(span, true, strs, Vec::new(), Vec::new())
 308     }
 309     fn path_all(&self,
 310                 sp: Span,
 311                 global: bool,
 312                 mut idents: Vec<ast::Ident> ,
 313                 lifetimes: Vec<ast::Lifetime>,
 314                 types: Vec<P<ast::Ty>> )
 315                 -> ast::Path {
 316         let last_identifier = idents.pop().unwrap();
 317         let mut segments: Vec<ast::PathSegment> = idents.move_iter()
 318                                                       .map(|ident| {
 319             ast::PathSegment {
 320                 identifier: ident,
 321                 lifetimes: Vec::new(),
 322                 types: OwnedSlice::empty(),
 323             }
 324         }).collect();
 325         segments.push(ast::PathSegment {
 326             identifier: last_identifier,
 327             lifetimes: lifetimes,
 328             types: OwnedSlice::from_vec(types),
 329         });
 330         ast::Path {
 331             span: sp,
 332             global: global,
 333             segments: segments,
 334         }
 335     }
 336
 337     fn ty_mt(&self, ty: P<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy {
 338         ast::MutTy {
 339             ty: ty,
 340             mutbl: mutbl
 341         }
 342     }
 343
 344     fn ty(&self, span: Span, ty: ast::Ty_) -> P<ast::Ty> {
 345         P(ast::Ty {
 346             id: ast::DUMMY_NODE_ID,
 347             span: span,
 348             node: ty
 349         })
 350     }
 351
 352     fn ty_path(&self, path: ast::Path, bounds: Option<OwnedSlice<ast::TyParamBound>>)
 353               -> P<ast::Ty> {
 354         self.ty(path.span,
 355                 ast::TyPath(path, bounds, ast::DUMMY_NODE_ID))
 356     }
 357
 358     // Might need to take bounds as an argument in the future, if you ever want
 359     // to generate a bounded existential trait type.
 360     fn ty_ident(&self, span: Span, ident: ast::Ident)
 361         -> P<ast::Ty> {
 362         self.ty_path(self.path_ident(span, ident), None)
 363     }
 364
 365     fn ty_rptr(&self,
 366                span: Span,
 367                ty: P<ast::Ty>,
 368                lifetime: Option<ast::Lifetime>,
 369                mutbl: ast::Mutability)
 370         -> P<ast::Ty> {
 371         self.ty(span,
 372                 ast::TyRptr(lifetime, self.ty_mt(ty, mutbl)))
 373     }
 374
 375     fn ty_ptr(&self,
 376               span: Span,
 377               ty: P<ast::Ty>,
 378               mutbl: ast::Mutability)
 379         -> P<ast::Ty> {
 380         self.ty(span,
 381                 ast::TyPtr(self.ty_mt(ty, mutbl)))
 382     }
 383     fn ty_uniq(&self, span: Span, ty: P<ast::Ty>) -> P<ast::Ty> {
 384         self.ty(span, ast::TyUniq(ty))
 385     }
 386
 387     fn ty_option(&self, ty: P<ast::Ty>) -> P<ast::Ty> {
 388         self.ty_path(
 389             self.path_all(DUMMY_SP,
 390                           true,
 391                           vec!(
 392                               self.ident_of("std"),
 393                               self.ident_of("option"),
 394                               self.ident_of("Option")
 395                           ),
 396                           Vec::new(),
 397                           vec!( ty )), None)
 398     }
 399
 400     fn ty_field_imm(&self, span: Span, name: Ident, ty: P<ast::Ty>) -> ast::TypeField {
 401         ast::TypeField {
 402             ident: name,
 403             mt: ast::MutTy { ty: ty, mutbl: ast::MutImmutable },
 404             span: span,
 405         }
 406     }
 407
 408     fn ty_infer(&self, span: Span) -> P<ast::Ty> {
 409         self.ty(span, ast::TyInfer)
 410     }
 411
 412     fn ty_nil(&self) -> P<ast::Ty> {
 413         P(ast::Ty {
 414             id: ast::DUMMY_NODE_ID,
 415             node: ast::TyNil,
 416             span: DUMMY_SP,
 417         })
 418     }
 419
 420     fn typaram(&self,
 421                span: Span,
 422                id: ast::Ident,
 423                bounds: OwnedSlice<ast::TyParamBound>,
 424                unbound: Option<ast::TyParamBound>,
 425                default: Option<P<ast::Ty>>) -> ast::TyParam {
 426         ast::TyParam {
 427             ident: id,
 428             id: ast::DUMMY_NODE_ID,
 429             bounds: bounds,
 430             unbound: unbound,
 431             default: default,
 432             span: span
 433         }
 434     }
 435
 436     // these are strange, and probably shouldn't be used outside of
 437     // pipes. Specifically, the global version possible generates
 438     // incorrect code.
 439     fn ty_vars(&self, ty_params: &OwnedSlice<ast::TyParam>) -> Vec<P<ast::Ty>> {
 440         ty_params.iter().map(|p| self.ty_ident(DUMMY_SP, p.ident)).collect()
 441     }
 442
 443     fn ty_vars_global(&self, ty_params: &OwnedSlice<ast::TyParam>) -> Vec<P<ast::Ty>> {
 444         ty_params.iter().map(|p| self.ty_path(
 445                 self.path_global(DUMMY_SP, vec!(p.ident)), None)).collect()
 446     }
 447
 448     fn strip_bounds(&self, generics: &Generics) -> Generics {
 449         let new_params = generics.ty_params.map(|ty_param| {
 450             ast::TyParam { bounds: OwnedSlice::empty(), unbound: None, ..*ty_param }
 451         });
 452         Generics {
 453             ty_params: new_params,
 454             .. (*generics).clone()
 455         }
 456     }
 457
 458     fn trait_ref(&self, path: ast::Path) -> ast::TraitRef {
 459         ast::TraitRef {
 460             path: path,
 461             ref_id: ast::DUMMY_NODE_ID
 462         }
 463     }
 464
 465     fn typarambound(&self, path: ast::Path) -> ast::TyParamBound {
 466         ast::TraitTyParamBound(self.trait_ref(path))
 467     }
 468
 469     fn lifetime(&self, span: Span, name: ast::Name) -> ast::Lifetime {
 470         ast::Lifetime { id: ast::DUMMY_NODE_ID, span: span, name: name }
 471     }
 472
 473     fn lifetime_def(&self,
 474                     span: Span,
 475                     name: ast::Name,
 476                     bounds: Vec<ast::Lifetime>)
 477                     -> ast::LifetimeDef {
 478         ast::LifetimeDef {
 479             lifetime: self.lifetime(span, name),
 480             bounds: bounds
 481         }
 482     }
 483
 484     fn stmt_expr(&self, expr: Gc<ast::Expr>) -> Gc<ast::Stmt> {
 485         box(GC) respan(expr.span, ast::StmtSemi(expr, ast::DUMMY_NODE_ID))
 486     }
 487
 488     fn stmt_let(&self, sp: Span, mutbl: bool, ident: ast::Ident,
 489                 ex: Gc<ast::Expr>) -> Gc<ast::Stmt> {
 490         let pat = if mutbl {
 491             self.pat_ident_binding_mode(sp, ident, ast::BindByValue(ast::MutMutable))
 492         } else {
 493             self.pat_ident(sp, ident)
 494         };
 495         let local = box(GC) ast::Local {
 496             ty: self.ty_infer(sp),
 497             pat: pat,
 498             init: Some(ex),
 499             id: ast::DUMMY_NODE_ID,
 500             span: sp,
 501             source: ast::LocalLet,
 502         };
 503         let decl = respan(sp, ast::DeclLocal(local));
 504         box(GC) respan(sp, ast::StmtDecl(box(GC) decl, ast::DUMMY_NODE_ID))
 505     }
 506
 507     fn stmt_let_typed(&self,
 508                       sp: Span,
 509                       mutbl: bool,
 510                       ident: ast::Ident,
 511                       typ: P<ast::Ty>,
 512                       ex: Gc<ast::Expr>)
 513                       -> Gc<ast::Stmt> {
 514         let pat = if mutbl {
 515             self.pat_ident_binding_mode(sp, ident, ast::BindByValue(ast::MutMutable))
 516         } else {
 517             self.pat_ident(sp, ident)
 518         };
 519         let local = box(GC) ast::Local {
 520             ty: typ,
 521             pat: pat,
 522             init: Some(ex),
 523             id: ast::DUMMY_NODE_ID,
 524             span: sp,
 525             source: ast::LocalLet,
 526         };
 527         let decl = respan(sp, ast::DeclLocal(local));
 528         box(GC) respan(sp, ast::StmtDecl(box(GC) decl, ast::DUMMY_NODE_ID))
 529     }
 530
 531     fn block(&self,
 532              span: Span,
 533              stmts: Vec<Gc<ast::Stmt>>,
 534              expr: Option<Gc<Expr>>)
 535              -> P<ast::Block> {
 536         self.block_all(span, Vec::new(), stmts, expr)
 537     }
 538
 539     fn stmt_item(&self, sp: Span, item: Gc<ast::Item>) -> Gc<ast::Stmt> {
 540         let decl = respan(sp, ast::DeclItem(item));
 541         box(GC) respan(sp, ast::StmtDecl(box(GC) decl, ast::DUMMY_NODE_ID))
 542     }
 543
 544     fn block_expr(&self, expr: Gc<ast::Expr>) -> P<ast::Block> {
 545         self.block_all(expr.span, Vec::new(), Vec::new(), Some(expr))
 546     }
 547     fn block_all(&self,
 548                  span: Span,
 549                  view_items: Vec<ast::ViewItem> ,
 550                  stmts: Vec<Gc<ast::Stmt>>,
 551                  expr: Option<Gc<ast::Expr>>) -> P<ast::Block> {
 552             P(ast::Block {
 553                view_items: view_items,
 554                stmts: stmts,
 555                expr: expr,
 556                id: ast::DUMMY_NODE_ID,
 557                rules: ast::DefaultBlock,
 558                span: span,
 559             })
 560     }
 561
 562     fn expr(&self, span: Span, node: ast::Expr_) -> Gc<ast::Expr> {
 563         box(GC) ast::Expr {
 564             id: ast::DUMMY_NODE_ID,
 565             node: node,
 566             span: span,
 567         }
 568     }
 569
 570     fn expr_path(&self, path: ast::Path) -> Gc<ast::Expr> {
 571         self.expr(path.span, ast::ExprPath(path))
 572     }
 573
 574     fn expr_ident(&self, span: Span, id: ast::Ident) -> Gc<ast::Expr> {
 575         self.expr_path(self.path_ident(span, id))
 576     }
 577     fn expr_self(&self, span: Span) -> Gc<ast::Expr> {
 578         self.expr_ident(span, special_idents::self_)
 579     }
 580
 581     fn expr_binary(&self, sp: Span, op: ast::BinOp,
 582                    lhs: Gc<ast::Expr>, rhs: Gc<ast::Expr>) -> Gc<ast::Expr> {
 583         self.expr(sp, ast::ExprBinary(op, lhs, rhs))
 584     }
 585
 586     fn expr_deref(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
 587         self.expr_unary(sp, ast::UnDeref, e)
 588     }
 589     fn expr_unary(&self, sp: Span, op: ast::UnOp, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
 590         self.expr(sp, ast::ExprUnary(op, e))
 591     }
 592
 593     fn expr_managed(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
 594         self.expr_unary(sp, ast::UnBox, e)
 595     }
 596
 597     fn expr_field_access(&self, sp: Span, expr: Gc<ast::Expr>, ident: ast::Ident) -> Gc<ast::Expr> {
 598         let field_name = token::get_ident(ident);
 599         let field_span = Span {
 600             lo: sp.lo - Pos::from_uint(field_name.get().len()),
 601             hi: sp.hi,
 602             expn_info: sp.expn_info,
 603         };
 604
 605         let id = Spanned { node: ident, span: field_span };
 606         self.expr(sp, ast::ExprField(expr, id, Vec::new()))
 607     }
 608     fn expr_addr_of(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
 609         self.expr(sp, ast::ExprAddrOf(ast::MutImmutable, e))
 610     }
 611     fn expr_mut_addr_of(&self, sp: Span, e: Gc<ast::Expr>) -> Gc<ast::Expr> {
 612         self.expr(sp, ast::ExprAddrOf(ast::MutMutable, e))
 613     }
 614
 615     fn expr_call(&self, span: Span, expr: Gc<ast::Expr>,
 616                  args: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr> {
 617         self.expr(span, ast::ExprCall(expr, args))
 618     }
 619     fn expr_call_ident(&self, span: Span, id: ast::Ident,
 620                        args: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr> {
 621         self.expr(span, ast::ExprCall(self.expr_ident(span, id), args))
 622     }
 623     fn expr_call_global(&self, sp: Span, fn_path: Vec<ast::Ident> ,
 624                       args: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr> {
 625         let pathexpr = self.expr_path(self.path_global(sp, fn_path));
 626         self.expr_call(sp, pathexpr, args)
 627     }
 628     fn expr_method_call(&self, span: Span,
 629                         expr: Gc<ast::Expr>,
 630                         ident: ast::Ident,
 631                         mut args: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr> {
 632         let id = Spanned { node: ident, span: span };
 633         args.unshift(expr);
 634         self.expr(span, ast::ExprMethodCall(id, Vec::new(), args))
 635     }
 636     fn expr_block(&self, b: P<ast::Block>) -> Gc<ast::Expr> {
 637         self.expr(b.span, ast::ExprBlock(b))
 638     }
 639     fn field_imm(&self, span: Span, name: Ident, e: Gc<ast::Expr>) -> ast::Field {
 640         ast::Field { ident: respan(span, name), expr: e, span: span }
 641     }
 642     fn expr_struct(&self, span: Span, path: ast::Path, fields: Vec<ast::Field> ) -> Gc<ast::Expr> {
 643         self.expr(span, ast::ExprStruct(path, fields, None))
 644     }
 645     fn expr_struct_ident(&self, span: Span,
 646                          id: ast::Ident, fields: Vec<ast::Field> ) -> Gc<ast::Expr> {
 647         self.expr_struct(span, self.path_ident(span, id), fields)
 648     }
 649
 650     fn expr_lit(&self, sp: Span, lit: ast::Lit_) -> Gc<ast::Expr> {
 651         self.expr(sp, ast::ExprLit(box(GC) respan(sp, lit)))
 652     }
 653     fn expr_uint(&self, span: Span, i: uint) -> Gc<ast::Expr> {
 654         self.expr_lit(span, ast::LitInt(i as u64, ast::UnsignedIntLit(ast::TyU)))
 655     }
 656     fn expr_int(&self, sp: Span, i: int) -> Gc<ast::Expr> {
 657         self.expr_lit(sp, ast::LitInt(i as u64, ast::SignedIntLit(ast::TyI, ast::Sign::new(i))))
 658     }
 659     fn expr_u8(&self, sp: Span, u: u8) -> Gc<ast::Expr> {
 660         self.expr_lit(sp, ast::LitInt(u as u64, ast::UnsignedIntLit(ast::TyU8)))
 661     }
 662     fn expr_bool(&self, sp: Span, value: bool) -> Gc<ast::Expr> {
 663         self.expr_lit(sp, ast::LitBool(value))
 664     }
 665
 666     fn expr_vec(&self, sp: Span, exprs: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr> {
 667         self.expr(sp, ast::ExprVec(exprs))
 668     }
 669     fn expr_vec_ng(&self, sp: Span) -> Gc<ast::Expr> {
 670         self.expr_call_global(sp,
 671                               vec!(self.ident_of("std"),
 672                                    self.ident_of("vec"),
 673                                    self.ident_of("Vec"),
 674                                    self.ident_of("new")),
 675                               Vec::new())
 676     }
 677     fn expr_vec_slice(&self, sp: Span, exprs: Vec<Gc<ast::Expr>> ) -> Gc<ast::Expr> {
 678         self.expr_addr_of(sp, self.expr_vec(sp, exprs))
 679     }
 680     fn expr_str(&self, sp: Span, s: InternedString) -> Gc<ast::Expr> {
 681         self.expr_lit(sp, ast::LitStr(s, ast::CookedStr))
 682     }
 683
 684     fn expr_cast(&self, sp: Span, expr: Gc<ast::Expr>, ty: P<ast::Ty>) -> Gc<ast::Expr> {
 685         self.expr(sp, ast::ExprCast(expr, ty))
 686     }
 687
 688
 689     fn expr_some(&self, sp: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr> {
 690         let some = vec!(
 691             self.ident_of("std"),
 692             self.ident_of("option"),
 693             self.ident_of("Some"));
 694         self.expr_call_global(sp, some, vec!(expr))
 695     }
 696
 697     fn expr_none(&self, sp: Span) -> Gc<ast::Expr> {
 698         let none = self.path_global(sp, vec!(
 699             self.ident_of("std"),
 700             self.ident_of("option"),
 701             self.ident_of("None")));
 702         self.expr_path(none)
 703     }
 704
 705     fn expr_tuple(&self, sp: Span, exprs: Vec<Gc<ast::Expr>>) -> Gc<ast::Expr> {
 706         self.expr(sp, ast::ExprTup(exprs))
 707     }
 708
 709     fn expr_fail(&self, span: Span, msg: InternedString) -> Gc<ast::Expr> {
 710         let loc = self.codemap().lookup_char_pos(span.lo);
 711         let expr_file = self.expr_str(span,
 712                                       token::intern_and_get_ident(loc.file
 713                                                                   .name
 714                                                                   .as_slice()));
 715         let expr_line = self.expr_uint(span, loc.line);
 716         let expr_file_line_tuple = self.expr_tuple(span, vec!(expr_file, expr_line));
 717         let expr_file_line_ptr = self.expr_addr_of(span, expr_file_line_tuple);
 718         self.expr_call_global(
 719             span,
 720             vec!(
 721                 self.ident_of("std"),
 722                 self.ident_of("rt"),
 723                 self.ident_of("begin_unwind")),
 724             vec!(
 725                 self.expr_str(span, msg),
 726                 expr_file_line_ptr))
 727     }
 728
 729     fn expr_unreachable(&self, span: Span) -> Gc<ast::Expr> {
 730         self.expr_fail(span,
 731                        InternedString::new(
 732                            "internal error: entered unreachable code"))
 733     }
 734
 735     fn expr_ok(&self, sp: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr> {
 736         let ok = vec!(
 737             self.ident_of("std"),
 738             self.ident_of("result"),
 739             self.ident_of("Ok"));
 740         self.expr_call_global(sp, ok, vec!(expr))
 741     }
 742
 743     fn expr_err(&self, sp: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr> {
 744         let err = vec!(
 745             self.ident_of("std"),
 746             self.ident_of("result"),
 747             self.ident_of("Err"));
 748         self.expr_call_global(sp, err, vec!(expr))
 749     }
 750
 751     fn expr_try(&self, sp: Span, head: Gc<ast::Expr>) -> Gc<ast::Expr> {
 752         let ok = self.ident_of("Ok");
 753         let ok_path = self.path_ident(sp, ok);
 754         let err = self.ident_of("Err");
 755         let err_path = self.path_ident(sp, err);
 756
 757         let binding_variable = self.ident_of("__try_var");
 758         let binding_pat = self.pat_ident(sp, binding_variable);
 759         let binding_expr = self.expr_ident(sp, binding_variable);
 760
 761         // Ok(__try_var) pattern
 762         let ok_pat = self.pat_enum(sp, ok_path, vec!(binding_pat));
 763
 764         // Err(__try_var)  (pattern and expression resp.)
 765         let err_pat = self.pat_enum(sp, err_path, vec!(binding_pat));
 766         let err_inner_expr = self.expr_call_ident(sp, err, vec!(binding_expr));
 767         // return Err(__try_var)
 768         let err_expr = self.expr(sp, ast::ExprRet(Some(err_inner_expr)));
 769
 770         // Ok(__try_var) => __try_var
 771         let ok_arm = self.arm(sp, vec!(ok_pat), binding_expr);
 772         // Err(__try_var) => return Err(__try_var)
 773         let err_arm = self.arm(sp, vec!(err_pat), err_expr);
 774
 775         // match head { Ok() => ..., Err() => ... }
 776         self.expr_match(sp, head, vec!(ok_arm, err_arm))
 777     }
 778
 779
 780     fn pat(&self, span: Span, pat: ast::Pat_) -> Gc<ast::Pat> {
 781         box(GC) ast::Pat { id: ast::DUMMY_NODE_ID, node: pat, span: span }
 782     }
 783     fn pat_wild(&self, span: Span) -> Gc<ast::Pat> {
 784         self.pat(span, ast::PatWild(ast::PatWildSingle))
 785     }
 786     fn pat_lit(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Pat> {
 787         self.pat(span, ast::PatLit(expr))
 788     }
 789     fn pat_ident(&self, span: Span, ident: ast::Ident) -> Gc<ast::Pat> {
 790         self.pat_ident_binding_mode(span, ident, ast::BindByValue(ast::MutImmutable))
 791     }
 792
 793     fn pat_ident_binding_mode(&self,
 794                               span: Span,
 795                               ident: ast::Ident,
 796                               bm: ast::BindingMode) -> Gc<ast::Pat> {
 797         let pat = ast::PatIdent(bm, Spanned{span: span, node: ident}, None);
 798         self.pat(span, pat)
 799     }
 800     fn pat_enum(&self, span: Span, path: ast::Path, subpats: Vec<Gc<ast::Pat>> ) -> Gc<ast::Pat> {
 801         let pat = ast::PatEnum(path, Some(subpats));
 802         self.pat(span, pat)
 803     }
 804     fn pat_struct(&self, span: Span,
 805                   path: ast::Path, field_pats: Vec<ast::FieldPat> ) -> Gc<ast::Pat> {
 806         let pat = ast::PatStruct(path, field_pats, false);
 807         self.pat(span, pat)
 808     }
 809     fn pat_tuple(&self, span: Span, pats: Vec<Gc<ast::Pat>>) -> Gc<ast::Pat> {
 810         let pat = ast::PatTup(pats);
 811         self.pat(span, pat)
 812     }
 813
 814     fn pat_some(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat> {
 815         let some = vec!(
 816             self.ident_of("std"),
 817             self.ident_of("option"),
 818             self.ident_of("Some"));
 819         let path = self.path_global(span, some);
 820         self.pat_enum(span, path, vec!(pat))
 821     }
 822
 823     fn pat_none(&self, span: Span) -> Gc<ast::Pat> {
 824         let some = vec!(
 825             self.ident_of("std"),
 826             self.ident_of("option"),
 827             self.ident_of("None"));
 828         let path = self.path_global(span, some);
 829         self.pat_enum(span, path, vec!())
 830     }
 831
 832     fn pat_ok(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat> {
 833         let some = vec!(
 834             self.ident_of("std"),
 835             self.ident_of("result"),
 836             self.ident_of("Ok"));
 837         let path = self.path_global(span, some);
 838         self.pat_enum(span, path, vec!(pat))
 839     }
 840
 841     fn pat_err(&self, span: Span, pat: Gc<ast::Pat>) -> Gc<ast::Pat> {
 842         let some = vec!(
 843             self.ident_of("std"),
 844             self.ident_of("result"),
 845             self.ident_of("Err"));
 846         let path = self.path_global(span, some);
 847         self.pat_enum(span, path, vec!(pat))
 848     }
 849
 850     fn arm(&self, _span: Span, pats: Vec<Gc<ast::Pat>> , expr: Gc<ast::Expr>) -> ast::Arm {
 851         ast::Arm {
 852             attrs: vec!(),
 853             pats: pats,
 854             guard: None,
 855             body: expr
 856         }
 857     }
 858
 859     fn arm_unreachable(&self, span: Span) -> ast::Arm {
 860         self.arm(span, vec!(self.pat_wild(span)), self.expr_unreachable(span))
 861     }
 862
 863     fn expr_match(&self, span: Span, arg: Gc<ast::Expr>,
 864                   arms: Vec<ast::Arm>) -> Gc<Expr> {
 865         self.expr(span, ast::ExprMatch(arg, arms))
 866     }
 867
 868     fn expr_if(&self, span: Span,
 869                cond: Gc<ast::Expr>, then: Gc<ast::Expr>,
 870                els: Option<Gc<ast::Expr>>) -> Gc<ast::Expr> {
 871         let els = els.map(|x| self.expr_block(self.block_expr(x)));
 872         self.expr(span, ast::ExprIf(cond, self.block_expr(then), els))
 873     }
 874
 875     fn expr_loop(&self, span: Span, block: P<ast::Block>) -> Gc<ast::Expr> {
 876         self.expr(span, ast::ExprLoop(block, None))
 877     }
 878
 879     fn lambda_fn_decl(&self, span: Span,
 880                       fn_decl: P<ast::FnDecl>, blk: P<ast::Block>) -> Gc<ast::Expr> {
 881         self.expr(span, ast::ExprFnBlock(ast::CaptureByRef, fn_decl, blk))
 882     }
 883     fn lambda(&self, span: Span, ids: Vec<ast::Ident> , blk: P<ast::Block>) -> Gc<ast::Expr> {
 884         let fn_decl = self.fn_decl(
 885             ids.iter().map(|id| self.arg(span, *id, self.ty_infer(span))).collect(),
 886             self.ty_infer(span));
 887
 888         self.expr(span, ast::ExprFnBlock(ast::CaptureByRef, fn_decl, blk))
 889     }
 890     fn lambda0(&self, span: Span, blk: P<ast::Block>) -> Gc<ast::Expr> {
 891         self.lambda(span, Vec::new(), blk)
 892     }
 893
 894     fn lambda1(&self, span: Span, blk: P<ast::Block>, ident: ast::Ident) -> Gc<ast::Expr> {
 895         self.lambda(span, vec!(ident), blk)
 896     }
 897
 898     fn lambda_expr(&self, span: Span, ids: Vec<ast::Ident> , expr: Gc<ast::Expr>) -> Gc<ast::Expr> {
 899         self.lambda(span, ids, self.block_expr(expr))
 900     }
 901     fn lambda_expr_0(&self, span: Span, expr: Gc<ast::Expr>) -> Gc<ast::Expr> {
 902         self.lambda0(span, self.block_expr(expr))
 903     }
 904     fn lambda_expr_1(&self, span: Span, expr: Gc<ast::Expr>, ident: ast::Ident) -> Gc<ast::Expr> {
 905         self.lambda1(span, self.block_expr(expr), ident)
 906     }
 907
 908     fn lambda_stmts(&self,
 909                     span: Span,
 910                     ids: Vec<ast::Ident>,
 911                     stmts: Vec<Gc<ast::Stmt>>)
 912                     -> Gc<ast::Expr> {
 913         self.lambda(span, ids, self.block(span, stmts, None))
 914     }
 915     fn lambda_stmts_0(&self, span: Span,
 916                       stmts: Vec<Gc<ast::Stmt>>) -> Gc<ast::Expr> {
 917         self.lambda0(span, self.block(span, stmts, None))
 918     }
 919     fn lambda_stmts_1(&self, span: Span, stmts: Vec<Gc<ast::Stmt>>,
 920                       ident: ast::Ident) -> Gc<ast::Expr> {
 921         self.lambda1(span, self.block(span, stmts, None), ident)
 922     }
 923
 924     fn arg(&self, span: Span, ident: ast::Ident, ty: P<ast::Ty>) -> ast::Arg {
 925         let arg_pat = self.pat_ident(span, ident);
 926         ast::Arg {
 927             ty: ty,
 928             pat: arg_pat,
 929             id: ast::DUMMY_NODE_ID
 930         }
 931     }
 932
 933     // FIXME unused self
 934     fn fn_decl(&self, inputs: Vec<ast::Arg> , output: P<ast::Ty>) -> P<ast::FnDecl> {
 935         P(ast::FnDecl {
 936             inputs: inputs,
 937             output: output,
 938             cf: ast::Return,
 939             variadic: false
 940         })
 941     }
 942
 943     fn item(&self, span: Span,
 944             name: Ident, attrs: Vec<ast::Attribute>,
 945             node: ast::Item_) -> Gc<ast::Item> {
 946         // FIXME: Would be nice if our generated code didn't violate
 947         // Rust coding conventions
 948         box(GC) ast::Item { ident: name,
 949                     attrs: attrs,
 950                     id: ast::DUMMY_NODE_ID,
 951                     node: node,
 952                     vis: ast::Inherited,
 953                     span: span }
 954     }
 955
 956     fn item_fn_poly(&self,
 957                     span: Span,
 958                     name: Ident,
 959                     inputs: Vec<ast::Arg> ,
 960                     output: P<ast::Ty>,
 961                     generics: Generics,
 962                     body: P<ast::Block>) -> Gc<ast::Item> {
 963         self.item(span,
 964                   name,
 965                   Vec::new(),
 966                   ast::ItemFn(self.fn_decl(inputs, output),
 967                               ast::NormalFn,
 968                               abi::Rust,
 969                               generics,
 970                               body))
 971     }
 972
 973     fn item_fn(&self,
 974                span: Span,
 975                name: Ident,
 976                inputs: Vec<ast::Arg> ,
 977                output: P<ast::Ty>,
 978                body: P<ast::Block>
 979               ) -> Gc<ast::Item> {
 980         self.item_fn_poly(
 981             span,
 982             name,
 983             inputs,
 984             output,
 985             ast_util::empty_generics(),
 986             body)
 987     }
 988
 989     fn variant(&self, span: Span, name: Ident, tys: Vec<P<ast::Ty>> ) -> ast::Variant {
 990         let args = tys.move_iter().map(|ty| {
 991             ast::VariantArg { ty: ty, id: ast::DUMMY_NODE_ID }
 992         }).collect();
 993
 994         respan(span,
 995                ast::Variant_ {
 996                    name: name,
 997                    attrs: Vec::new(),
 998                    kind: ast::TupleVariantKind(args),
 999                    id: ast::DUMMY_NODE_ID,
1000                    disr_expr: None,
1001                    vis: ast::Public
1002                })
1003     }
1004
1005     fn item_enum_poly(&self, span: Span, name: Ident,
1006                       enum_definition: ast::EnumDef,
1007                       generics: Generics) -> Gc<ast::Item> {
1008         self.item(span, name, Vec::new(), ast::ItemEnum(enum_definition, generics))
1009     }
1010
1011     fn item_enum(&self, span: Span, name: Ident,
1012                  enum_definition: ast::EnumDef) -> Gc<ast::Item> {
1013         self.item_enum_poly(span, name, enum_definition,
1014                             ast_util::empty_generics())
1015     }
1016
1017     fn item_struct(&self, span: Span, name: Ident,
1018                    struct_def: ast::StructDef) -> Gc<ast::Item> {
1019         self.item_struct_poly(
1020             span,
1021             name,
1022             struct_def,
1023             ast_util::empty_generics()
1024         )
1025     }
1026
1027     fn item_struct_poly(&self, span: Span, name: Ident,
1028         struct_def: ast::StructDef, generics: Generics) -> Gc<ast::Item> {
1029         self.item(span, name, Vec::new(), ast::ItemStruct(box(GC) struct_def, generics))
1030     }
1031
1032     fn item_mod(&self, span: Span, inner_span: Span, name: Ident,
1033                 attrs: Vec<ast::Attribute> ,
1034                 vi: Vec<ast::ViewItem> ,
1035                 items: Vec<Gc<ast::Item>>) -> Gc<ast::Item> {
1036         self.item(
1037             span,
1038             name,
1039             attrs,
1040             ast::ItemMod(ast::Mod {
1041                 inner: inner_span,
1042                 view_items: vi,
1043                 items: items,
1044             })
1045         )
1046     }
1047
1048     fn item_static(&self,
1049                    span: Span,
1050                    name: Ident,
1051                    ty: P<ast::Ty>,
1052                    mutbl: ast::Mutability,
1053                    expr: Gc<ast::Expr>)
1054                    -> Gc<ast::Item> {
1055         self.item(span, name, Vec::new(), ast::ItemStatic(ty, mutbl, expr))
1056     }
1057
1058     fn item_ty_poly(&self, span: Span, name: Ident, ty: P<ast::Ty>,
1059                     generics: Generics) -> Gc<ast::Item> {
1060         self.item(span, name, Vec::new(), ast::ItemTy(ty, generics))
1061     }
1062
1063     fn item_ty(&self, span: Span, name: Ident, ty: P<ast::Ty>) -> Gc<ast::Item> {
1064         self.item_ty_poly(span, name, ty, ast_util::empty_generics())
1065     }
1066
1067     fn attribute(&self, sp: Span, mi: Gc<ast::MetaItem>) -> ast::Attribute {
1068         respan(sp, ast::Attribute_ {
1069             id: attr::mk_attr_id(),
1070             style: ast::AttrOuter,
1071             value: mi,
1072             is_sugared_doc: false,
1073         })
1074     }
1075
1076     fn meta_word(&self, sp: Span, w: InternedString) -> Gc<ast::MetaItem> {
1077         box(GC) respan(sp, ast::MetaWord(w))
1078     }
1079     fn meta_list(&self,
1080                  sp: Span,
1081                  name: InternedString,
1082                  mis: Vec<Gc<ast::MetaItem>> )
1083                  -> Gc<ast::MetaItem> {
1084         box(GC) respan(sp, ast::MetaList(name, mis))
1085     }
1086     fn meta_name_value(&self,
1087                        sp: Span,
1088                        name: InternedString,
1089                        value: ast::Lit_)
1090                        -> Gc<ast::MetaItem> {
1091         box(GC) respan(sp, ast::MetaNameValue(name, respan(sp, value)))
1092     }
1093
1094     fn view_use(&self, sp: Span,
1095                 vis: ast::Visibility, vp: Gc<ast::ViewPath>) -> ast::ViewItem {
1096         ast::ViewItem {
1097             node: ast::ViewItemUse(vp),
1098             attrs: Vec::new(),
1099             vis: vis,
1100             span: sp
1101         }
1102     }
1103
1104     fn view_use_simple(&self, sp: Span, vis: ast::Visibility, path: ast::Path) -> ast::ViewItem {
1105         let last = path.segments.last().unwrap().identifier;
1106         self.view_use_simple_(sp, vis, last, path)
1107     }
1108
1109     fn view_use_simple_(&self, sp: Span, vis: ast::Visibility,
1110                         ident: ast::Ident, path: ast::Path) -> ast::ViewItem {
1111         self.view_use(sp, vis,
1112                       box(GC) respan(sp,
1113                            ast::ViewPathSimple(ident,
1114                                                path,
1115                                                ast::DUMMY_NODE_ID)))
1116     }
1117
1118     fn view_use_list(&self, sp: Span, vis: ast::Visibility,
1119                      path: Vec<ast::Ident> , imports: &[ast::Ident]) -> ast::ViewItem {
1120         let imports = imports.iter().map(|id| {
1121             respan(sp, ast::PathListIdent { name: *id, id: ast::DUMMY_NODE_ID })
1122         }).collect();
1123
1124         self.view_use(sp, vis,
1125                       box(GC) respan(sp,
1126                            ast::ViewPathList(self.path(sp, path),
1127                                              imports,
1128                                              ast::DUMMY_NODE_ID)))
1129     }
1130
1131     fn view_use_glob(&self, sp: Span,
1132                      vis: ast::Visibility, path: Vec<ast::Ident> ) -> ast::ViewItem {
1133         self.view_use(sp, vis,
1134                       box(GC) respan(sp,
1135                            ast::ViewPathGlob(self.path(sp, path), ast::DUMMY_NODE_ID)))
1136     }
1137 }
1138
1139 struct Duplicator<'a>;
1140
1141 impl<'a> Folder for Duplicator<'a> {
1142     fn new_id(&mut self, _: NodeId) -> NodeId {
1143         ast::DUMMY_NODE_ID
1144     }
1145 }
1146
1147 pub trait Duplicate {
1148     //
1149     // Duplication functions
1150     //
1151     // These functions just duplicate AST nodes.
1152     //
1153
1154     fn duplicate(&self, cx: &ExtCtxt) -> Self;
1155 }
1156
1157 impl Duplicate for Gc<ast::Expr> {
1158     fn duplicate(&self, _: &ExtCtxt) -> Gc<ast::Expr> {
1159         let mut folder = Duplicator;
1160         folder.fold_expr(*self)
1161     }
1162 }