mcs/gmcs/generic.cs

   1 //
   2 // generic.cs: Support classes for generics
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2003 Ximian, Inc.
   8 //
   9 using System;
  10 using System.Reflection;
  11 using System.Reflection.Emit;
  12 using System.Globalization;
  13 using System.Collections;
  14 using System.Text;
  15
  16 namespace Mono.CSharp {
  17
  18         //
  19         // Tracks the constraints for a type parameter
  20         //
  21         public class Constraints {
  22                 string type_parameter;
  23                 ArrayList constraints;
  24                 Location loc;
  25
  26                 //
  27                 // type_parameter is the identifier, constraints is an arraylist of
  28                 // Expressions (with types) or `true' for the constructor constraint.
  29                 //
  30                 public Constraints (string type_parameter, ArrayList constraints,
  31                                     Location loc)
  32                 {
  33                         this.type_parameter = type_parameter;
  34                         this.constraints = constraints;
  35                         this.loc = loc;
  36                 }
  37
  38                 public string TypeParameter {
  39                         get {
  40                                 return type_parameter;
  41                         }
  42                 }
  43
  44                 protected void Error (string message)
  45                 {
  46                         Report.Error (-218, "Invalid constraints clause for type " +
  47                                       "parameter `{0}': {1}", type_parameter, message);
  48                 }
  49
  50                 bool has_ctor_constraint;
  51                 Type class_constraint;
  52                 ArrayList iface_constraints;
  53                 Type[] constraint_types;
  54                 int num_constraints;
  55
  56                 public bool HasConstructorConstraint {
  57                         get { return has_ctor_constraint; }
  58                 }
  59
  60                 public Type[] Types {
  61                         get { return constraint_types; }
  62                 }
  63
  64                 public bool Resolve (TypeContainer tc)
  65                 {
  66                         iface_constraints = new ArrayList ();
  67
  68                         if (constraints == null) {
  69                                 constraint_types = new Type [0];
  70                                 return true;
  71                         }
  72
  73                         foreach (object obj in constraints) {
  74                                 if (has_ctor_constraint) {
  75                                         Error ("can only use one constructor constraint and " +
  76                                                "it must be the last constraint in the list.");
  77                                         return false;
  78                                 }
  79
  80                                 if (obj is bool) {
  81                                         has_ctor_constraint = true;
  82                                         continue;
  83                                 }
  84
  85                                 Expression expr = tc.ResolveTypeExpr ((Expression) obj, false, loc);
  86                                 if (expr == null)
  87                                         return false;
  88
  89                                 Type etype = expr.Type;
  90                                 if (etype.IsInterface)
  91                                         iface_constraints.Add (etype);
  92                                 else if (class_constraint != null) {
  93                                         Error ("can have at most one class constraint.");
  94                                         return false;
  95                                 } else
  96                                         class_constraint = etype;
  97
  98                                 num_constraints++;
  99                         }
 100
 101                         constraint_types = new Type [num_constraints];
 102                         int pos = 0;
 103                         if (class_constraint != null)
 104                                 constraint_types [pos++] = class_constraint;
 105                         iface_constraints.CopyTo (constraint_types, pos);
 106
 107                         return true;
 108                 }
 109         }
 110
 111         //
 112         // This type represents a generic type parameter
 113         //
 114         public class TypeParameter {
 115                 string name;
 116                 Constraints constraints;
 117                 Location loc;
 118                 Type type;
 119
 120                 public TypeParameter (string name, Constraints constraints, Location loc)
 121                 {
 122                         this.name = name;
 123                         this.constraints = constraints;
 124                         this.loc = loc;
 125                 }
 126
 127                 public string Name {
 128                         get {
 129                                 return name;
 130                         }
 131                 }
 132
 133                 public Location Location {
 134                         get {
 135                                 return loc;
 136                         }
 137                 }
 138
 139                 public Constraints Constraints {
 140                         get {
 141                                 return constraints;
 142                         }
 143                 }
 144
 145                 public Type Type {
 146                         get {
 147                                 return type;
 148                         }
 149                 }
 150
 151                 public bool Resolve (TypeContainer tc)
 152                 {
 153                         if (constraints != null)
 154                                 return constraints.Resolve (tc);
 155
 156                         return true;
 157                 }
 158
 159                 public Type Define (TypeBuilder tb)
 160                 {
 161                         if (constraints != null)
 162                                 type = tb.DefineGenericParameter (name, constraints.Types);
 163                         else
 164                                 type = tb.DefineGenericParameter (name, new Type [0]);
 165
 166                         return type;
 167                 }
 168
 169                 public Type DefineMethod (MethodBuilder mb)
 170                 {
 171                         if (constraints != null)
 172                                 type = mb.DefineGenericParameter (name, constraints.Types);
 173                         else
 174                                 type = mb.DefineGenericParameter (name, new Type [0]);
 175
 176                         return type;
 177                 }
 178
 179                 public override string ToString ()
 180                 {
 181                         return "TypeParameter[" + name + "]";
 182                 }
 183         }
 184
 185         //
 186         // This type represents a generic type parameter reference.
 187         //
 188         // These expressions are born in a fully resolved state.
 189         //
 190         public class TypeParameterExpr : TypeExpr {
 191                 TypeParameter type_parameter;
 192
 193                 public string Name {
 194                         get {
 195                                 return type_parameter.Name;
 196                         }
 197                 }
 198
 199                 public TypeParameter TypeParameter {
 200                         get {
 201                                 return type_parameter;
 202                         }
 203                 }
 204
 205                 public TypeParameterExpr (TypeParameter type_parameter, Location loc)
 206                         : base (type_parameter.Type, loc)
 207                 {
 208                         this.type_parameter = type_parameter;
 209                 }
 210
 211                 public override Expression ResolveAsTypeStep (EmitContext ec)
 212                 {
 213                         type = type_parameter.Type;
 214
 215                         return this;
 216                 }
 217
 218                 public override string ToString ()
 219                 {
 220                         return "TypeParameterExpr[" + type_parameter.Name + "]";
 221                 }
 222
 223                 public void Error_CannotUseAsUnmanagedType (Location loc)
 224                 {
 225                         Report.Error (-203, loc, "Can not use type parameter as unamanged type");
 226                 }
 227         }
 228
 229         public class TypeArguments {
 230                 ArrayList args;
 231                 Type[] atypes;
 232                 bool has_type_args;
 233
 234                 public TypeArguments ()
 235                 {
 236                         args = new ArrayList ();
 237                 }
 238
 239                 public void Add (Expression type)
 240                 {
 241                         args.Add (type);
 242                 }
 243
 244                 public Type[] Arguments {
 245                         get {
 246                                 return atypes;
 247                         }
 248                 }
 249
 250                 public bool HasTypeArguments {
 251                         get {
 252                                 return has_type_args;
 253                         }
 254                 }
 255
 256                 public override string ToString ()
 257                 {
 258                         StringBuilder s = new StringBuilder ();
 259
 260                         int count = args.Count;
 261                         for (int i = 0; i < count; i++){
 262                                 //
 263                                 // FIXME: Use TypeManager.CSharpname once we have the type
 264                                 //
 265                                 s.Append (args [i].ToString ());
 266                                 if (i+1 < count)
 267                                         s.Append (", ");
 268                         }
 269                         return s.ToString ();
 270                 }
 271
 272                 public bool Resolve (EmitContext ec)
 273                 {
 274                         int count = args.Count;
 275                         bool ok = true;
 276
 277                         atypes = new Type [count];
 278
 279                         for (int i = 0; i < count; i++){
 280                                 Expression e = ((Expression)args [i]).ResolveAsTypeTerminal (ec);
 281                                 if (e == null)
 282                                         ok = false;
 283                                 if (e is TypeParameterExpr)
 284                                         has_type_args = true;
 285                                 args [i] = e;
 286                                 atypes [i] = e.Type;
 287                         }
 288                         return ok;
 289                 }
 290         }
 291
 292         public class ConstructedType : Expression {
 293                 Expression container_type;
 294                 string name, full_name;
 295                 TypeArguments args;
 296                 Type[] gen_params, atypes;
 297
 298                 public ConstructedType (string name, TypeArguments args, Location l)
 299                 {
 300                         loc = l;
 301                         this.container_type = container_type;
 302                         this.name = name;
 303                         this.args = args;
 304                         eclass = ExprClass.Type;
 305
 306                         full_name = name + "<" + args.ToString () + ">";
 307                 }
 308
 309                 public override Expression DoResolve (EmitContext ec)
 310                 {
 311                         if (args.Resolve (ec) == false)
 312                                 return null;
 313
 314                         //
 315                         // Pretend there are not type parameters, until we get GetType support
 316                         //
 317                         return new SimpleName (name, loc).DoResolve (ec);
 318                 }
 319
 320                 protected bool CheckConstraints (int index)
 321                 {
 322                         Type atype = args.Arguments [index];
 323                         Type ptype = gen_params [index];
 324
 325                         //// FIXME
 326                         return true;
 327
 328                         //
 329                         // First, check parent class.
 330                         //
 331                         if ((ptype.BaseType != atype.BaseType) &&
 332                             !atype.BaseType.IsSubclassOf (ptype.BaseType)) {
 333                                 Report.Error (-219, loc, "Cannot create constructed type `{0}': " +
 334                                               "type argument `{1}' must derive from `{2}'.",
 335                                               full_name, atype, ptype.BaseType);
 336                                 return false;
 337                         }
 338
 339                         //
 340                         // Now, check the interfaces.
 341                         //
 342                         foreach (Type itype in ptype.GetInterfaces ()) {
 343                                 if (TypeManager.ImplementsInterface (atype, itype))
 344                                         continue;
 345
 346                                 Report.Error (-219, loc, "Cannot create constructed type `{0}: " +
 347                                               "type argument `{1}' must implement interface `{2}'.",
 348                                               full_name, atype, itype);
 349                                 return false;
 350                         }
 351
 352                         return true;
 353                 }
 354
 355                 public override Expression ResolveAsTypeStep (EmitContext ec)
 356                 {
 357                         if (args.Resolve (ec) == false)
 358                                 return null;
 359
 360                         //
 361                         // First, resolve the generic type.
 362                         //
 363                         SimpleName sn = new SimpleName (name, loc);
 364                         Expression resolved = sn.ResolveAsTypeStep (ec);
 365                         if (resolved == null)
 366                                 return null;
 367
 368                         Type gt = resolved.Type.GetGenericTypeDefinition ();
 369                         gen_params = gt.GetGenericArguments ();
 370                         atypes = args.Arguments;
 371
 372                         if (atypes.Length != gen_params.Length) {
 373                                 Report.Error (-217, loc, "Generic type `{0}' takes {1} " +
 374                                               "type parameters, but specified {2}.", gt.Name,
 375                                               gen_params.Length, atypes.Length);
 376                                 return null;
 377                         }
 378
 379                         if (args.HasTypeArguments)
 380                                 return new TypeExpr (gt, loc);
 381
 382                         for (int i = 0; i < gen_params.Length; i++) {
 383                                 if (!CheckConstraints (i))
 384                                         return null;
 385                         }
 386
 387                         //
 388                         // Now bind the parameters.
 389                         //
 390                         Type ntype = gt.BindGenericParameters (args.Arguments);
 391                         return new TypeExpr (ntype, loc);
 392                 }
 393
 394                 public override void Emit (EmitContext ec)
 395                 {
 396                         //
 397                         // Never reached for now
 398                         //
 399                         throw new Exception ("IMPLEMENT ME");
 400                 }
 401
 402                 public override string ToString ()
 403                 {
 404                         return full_name;
 405                 }
 406         }
 407
 408         public class GenericMethod : DeclSpace
 409         {
 410                 public GenericMethod (NamespaceEntry ns, TypeContainer parent, string name, Location l)
 411                         : base (ns, parent, name, l)
 412                 { }
 413
 414                 public override TypeBuilder DefineType ()
 415                 {
 416                         throw new Exception ();
 417                 }
 418
 419                 public override bool Define (TypeContainer parent)
 420                 {
 421                         return true;
 422                 }
 423
 424                 public bool Define (MethodBuilder mb)
 425                 {
 426                         Type[] gen_params = new Type [TypeParameters.Length];
 427                         for (int i = 0; i < TypeParameters.Length; i++)
 428                                 gen_params [i] = TypeParameters [i].DefineMethod (mb);
 429
 430                         return true;
 431                 }
 432
 433                 public override bool DefineMembers (TypeContainer parent)
 434                 {
 435                         return true;
 436                 }
 437
 438                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 439                                                         MemberFilter filter, object criteria)
 440                 {
 441                         throw new Exception ();
 442                 }
 443
 444                 public override MemberCache MemberCache {
 445                         get {
 446                                 throw new Exception ();
 447                         }
 448                 }
 449         }
 450
 451         public class GenericMemberAccess : MemberAccess
 452         {
 453                 TypeArguments args;
 454
 455                 public GenericMemberAccess (Expression expr, string id, TypeArguments args, Location loc)
 456                         : base (expr, id, loc)
 457                 {
 458                         this.args = args;
 459                 }
 460
 461                 public override Expression DoResolve (EmitContext ec, Expression right_side,
 462                                                       ResolveFlags flags)
 463                 {
 464                         Expression expr = base.DoResolve (ec, right_side, flags);
 465                         if (expr == null)
 466                                 return null;
 467
 468                         MethodGroupExpr mg = expr as MethodGroupExpr;
 469                         if (mg == null) {
 470                                 Report.Error (-220, loc, "Member `{0}' has type arguments, but did " +
 471                                               "not resolve as a method group.", Identifier);
 472                                 return null;
 473                         }
 474
 475                         Report.Debug (64, "RESOLVE GENERIC MEMBER ACCESS", expr, expr.GetType ());
 476
 477                         return expr;
 478                 }
 479         }
 480 }