vala/valaforeachstatement.vala

   1 /* valaforeachstatement.vala
   2  *
   3  * Copyright (C) 2006-2010  Jürg Billeter
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  18  *
  19  * Author:
  20  *      Jürg Billeter <j@bitron.ch>
  21  */
  22
  23
  24 /**
  25  * Represents a foreach statement in the source code. Foreach statements iterate
  26  * over the elements of a collection.
  27  */
  28 public class Vala.ForeachStatement : Block {
  29         /**
  30          * Specifies the element type.
  31          */
  32         public DataType? type_reference {
  33                 get { return _data_type; }
  34                 set {
  35                         _data_type = value;
  36                         if (_data_type != null) {
  37                                 _data_type.parent_node = this;
  38                         }
  39                 }
  40         }
  41
  42         /**
  43          * Specifies the element variable name.
  44          */
  45         public string variable_name { get; set; }
  46
  47         /**
  48          * Specifies the container.
  49          */
  50         public Expression collection {
  51                 get {
  52                         return _collection;
  53                 }
  54                 set {
  55                         _collection = value;
  56                         _collection.parent_node = this;
  57                 }
  58         }
  59
  60         /**
  61          * Specifies the loop body.
  62          */
  63         public Block body {
  64                 get {
  65                         return _body;
  66                 }
  67                 set {
  68                         _body = value;
  69                         _body.parent_node = this;
  70                 }
  71         }
  72
  73         public bool use_iterator { get; private set; }
  74
  75         /**
  76          * Specifies the declarator for the generated element variable.
  77          */
  78         public LocalVariable element_variable { get; set; }
  79
  80         /**
  81          * Specifies the declarator for the generated collection variable.
  82          */
  83         public LocalVariable collection_variable { get; set; }
  84
  85         /**
  86          * Specifies the declarator for the generated iterator variable.
  87          */
  88         public LocalVariable iterator_variable { get; set; }
  89
  90         private Expression _collection;
  91         private Block _body;
  92
  93         private DataType _data_type;
  94
  95         /**
  96          * Creates a new foreach statement.
  97          *
  98          * @param type   element type
  99          * @param id     element variable name
 100          * @param col    loop body
 101          * @param source reference to source code
 102          * @return       newly created foreach statement
 103          */
 104         public ForeachStatement (DataType? type_reference, string variable_name, Expression collection, Block body, SourceReference source_reference) {
 105                 base (source_reference);
 106                 this.variable_name = variable_name;
 107                 this.collection = collection;
 108                 this.body = body;
 109                 this.type_reference = type_reference;
 110         }
 111
 112         public override void accept (CodeVisitor visitor) {
 113                 if (use_iterator) {
 114                         base.accept (visitor);
 115                         return;
 116                 }
 117
 118                 visitor.visit_foreach_statement (this);
 119         }
 120
 121         public override void accept_children (CodeVisitor visitor) {
 122                 if (use_iterator) {
 123                         base.accept_children (visitor);
 124                         return;
 125                 }
 126
 127                 collection.accept (visitor);
 128                 visitor.visit_end_full_expression (collection);
 129
 130                 if (type_reference != null) {
 131                         type_reference.accept (visitor);
 132                 }
 133
 134                 body.accept (visitor);
 135         }
 136
 137         public override void replace_expression (Expression old_node, Expression new_node) {
 138                 if (collection == old_node) {
 139                         collection = new_node;
 140                 }
 141         }
 142
 143         public override void replace_type (DataType old_type, DataType new_type) {
 144                 if (type_reference == old_type) {
 145                         type_reference = new_type;
 146                 }
 147         }
 148
 149         public override bool check (CodeContext context) {
 150                 if (checked) {
 151                         return !error;
 152                 }
 153
 154                 checked = true;
 155
 156                 // analyze collection expression first, used for type inference
 157                 if (!collection.check (context)) {
 158                         // ignore inner error
 159                         error = true;
 160                         return false;
 161                 } else if (collection.value_type == null) {
 162                         Report.error (collection.source_reference, "invalid collection expression");
 163                         error = true;
 164                         return false;
 165                 }
 166
 167                 var collection_type = collection.value_type.copy ();
 168                 collection.target_type = collection_type.copy ();
 169
 170                 if (context.profile != Profile.DOVA && collection_type.is_array ()) {
 171                         var array_type = (ArrayType) collection_type;
 172
 173                         // can't use inline-allocated array for temporary variable
 174                         array_type.inline_allocated = false;
 175
 176                         return check_without_iterator (context, collection_type, array_type.element_type);
 177                 } else if (context.profile == Profile.GOBJECT && (collection_type.compatible (context.analyzer.glist_type) || collection_type.compatible (context.analyzer.gslist_type))) {
 178                         if (collection_type.get_type_arguments ().size != 1) {
 179                                 error = true;
 180                                 Report.error (collection.source_reference, "missing type argument for collection");
 181                                 return false;
 182                         }
 183
 184                         return check_without_iterator (context, collection_type, collection_type.get_type_arguments ().get (0));
 185                 } else if (context.profile == Profile.GOBJECT && collection_type.compatible (context.analyzer.gvaluearray_type)) {
 186                         return check_without_iterator (context, collection_type, context.analyzer.gvalue_type);
 187                 } else {
 188                         return check_with_iterator (context, collection_type);
 189                 }
 190         }
 191
 192         bool check_with_index (CodeContext context, DataType collection_type) {
 193                 var get_method = collection_type.get_member ("get") as Method;
 194                 if (get_method == null) {
 195                         return false;
 196                 }
 197                 if (get_method.get_parameters ().size != 1) {
 198                         return false;
 199                 }
 200                 var size_property = collection_type.get_member ("size") as Property;
 201                 if (size_property == null) {
 202                         return false;
 203                 }
 204
 205                 add_statement (new DeclarationStatement (new LocalVariable (null, "_%s_list".printf (variable_name), collection, source_reference), source_reference));
 206                 add_statement (new DeclarationStatement (new LocalVariable (null, "_%s_size".printf (variable_name), new MemberAccess (new MemberAccess.simple ("_%s_list".printf (variable_name), source_reference), "size", source_reference), source_reference), source_reference));
 207                 add_statement (new DeclarationStatement (new LocalVariable (null, "_%s_index".printf (variable_name), new UnaryExpression (UnaryOperator.MINUS, new IntegerLiteral ("1", source_reference), source_reference), source_reference), source_reference));
 208                 var next = new UnaryExpression (UnaryOperator.INCREMENT, new MemberAccess.simple ("_%s_index".printf (variable_name), source_reference), source_reference);
 209                 var conditional = new BinaryExpression (BinaryOperator.LESS_THAN, next, new MemberAccess.simple ("_%s_size".printf (variable_name), source_reference), source_reference);
 210                 var loop = new WhileStatement (conditional, body, source_reference);
 211                 add_statement (loop);
 212
 213                 var get_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_list".printf (variable_name), source_reference), "get", source_reference), source_reference);
 214                 get_call.add_argument (new MemberAccess.simple ("_%s_index".printf (variable_name), source_reference));
 215                 body.insert_statement (0, new DeclarationStatement (new LocalVariable (type_reference, variable_name, get_call, source_reference), source_reference));
 216
 217                 checked = false;
 218                 return base.check (context);
 219         }
 220
 221         bool check_with_iterator (CodeContext context, DataType collection_type) {
 222                 use_iterator = true;
 223
 224                 if (check_with_index (context, collection_type)) {
 225                         return true;
 226                 }
 227
 228                 var iterator_method = collection_type.get_member ("iterator") as Method;
 229                 if (iterator_method == null) {
 230                         Report.error (collection.source_reference, "`%s' does not have an `iterator' method".printf (collection_type.to_string ()));
 231                         error = true;
 232                         return false;
 233                 }
 234                 if (iterator_method.get_parameters ().size != 0) {
 235                         Report.error (collection.source_reference, "`%s' must not have any parameters".printf (iterator_method.get_full_name ()));
 236                         error = true;
 237                         return false;
 238                 }
 239                 var iterator_type = iterator_method.return_type.get_actual_type (collection_type, null, this);
 240                 if (iterator_type is VoidType) {
 241                         Report.error (collection.source_reference, "`%s' must return an iterator".printf (iterator_method.get_full_name ()));
 242                         error = true;
 243                         return false;
 244                 }
 245
 246                 var iterator_call = new MethodCall (new MemberAccess (collection, "iterator", source_reference), source_reference);
 247                 add_statement (new DeclarationStatement (new LocalVariable (iterator_type, "_%s_it".printf (variable_name), iterator_call, source_reference), source_reference));
 248
 249                 var next_value_method = iterator_type.get_member ("next_value") as Method;
 250                 var next_method = iterator_type.get_member ("next") as Method;
 251                 if (next_value_method != null) {
 252                         if (next_value_method.get_parameters ().size != 0) {
 253                                 Report.error (collection.source_reference, "`%s' must not have any parameters".printf (next_value_method.get_full_name ()));
 254                                 error = true;
 255                                 return false;
 256                         }
 257                         var element_type = next_value_method.return_type.get_actual_type (iterator_type, null, this);
 258                         if (!element_type.nullable) {
 259                                 Report.error (collection.source_reference, "return type of `%s' must be nullable".printf (next_value_method.get_full_name ()));
 260                                 error = true;
 261                                 return false;
 262                         }
 263
 264                         if (!analyze_element_type (element_type)) {
 265                                 return false;
 266                         }
 267
 268                         add_statement (new DeclarationStatement (new LocalVariable (type_reference, variable_name, null, source_reference), source_reference));
 269
 270                         var next_value_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "next_value", source_reference), source_reference);
 271                         var assignment = new Assignment (new MemberAccess (null, variable_name, source_reference), next_value_call, AssignmentOperator.SIMPLE, source_reference);
 272                         var conditional = new BinaryExpression (BinaryOperator.INEQUALITY, assignment, new NullLiteral (source_reference), source_reference);
 273                         var loop = new WhileStatement (conditional, body, source_reference);
 274                         add_statement (loop);
 275                 } else if (next_method != null) {
 276                         if (next_method.get_parameters ().size != 0) {
 277                                 Report.error (collection.source_reference, "`%s' must not have any parameters".printf (next_method.get_full_name ()));
 278                                 error = true;
 279                                 return false;
 280                         }
 281                         if (!next_method.return_type.compatible (context.analyzer.bool_type)) {
 282                                 Report.error (collection.source_reference, "`%s' must return a boolean value".printf (next_method.get_full_name ()));
 283                                 error = true;
 284                                 return false;
 285                         }
 286                         var get_method = iterator_type.get_member ("get") as Method;
 287                         if (get_method == null) {
 288                                 Report.error (collection.source_reference, "`%s' does not have a `get' method".printf (iterator_type.to_string ()));
 289                                 error = true;
 290                                 return false;
 291                         }
 292                         if (get_method.get_parameters ().size != 0) {
 293                                 Report.error (collection.source_reference, "`%s' must not have any parameters".printf (get_method.get_full_name ()));
 294                                 error = true;
 295                                 return false;
 296                         }
 297                         var element_type = get_method.return_type.get_actual_type (iterator_type, null, this);
 298                         if (element_type is VoidType) {
 299                                 Report.error (collection.source_reference, "`%s' must return an element".printf (get_method.get_full_name ()));
 300                                 error = true;
 301                                 return false;
 302                         }
 303
 304                         if (!analyze_element_type (element_type)) {
 305                                 return false;
 306                         }
 307
 308                         var next_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "next", source_reference), source_reference);
 309                         var loop = new WhileStatement (next_call, body, source_reference);
 310                         add_statement (loop);
 311
 312                         var get_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "get", source_reference), source_reference);
 313                         body.insert_statement (0, new DeclarationStatement (new LocalVariable (type_reference, variable_name, get_call, source_reference), source_reference));
 314                 } else {
 315                         Report.error (collection.source_reference, "`%s' does not have a `next_value' or `next' method".printf (iterator_type.to_string ()));
 316                         error = true;
 317                         return false;
 318                 }
 319
 320                 checked = false;
 321                 return base.check (context);
 322         }
 323
 324         bool analyze_element_type (DataType element_type) {
 325                 // analyze element type
 326                 if (type_reference == null) {
 327                         // var type
 328                         type_reference = element_type.copy ();
 329                 } else if (!element_type.compatible (type_reference)) {
 330                         error = true;
 331                         Report.error (source_reference, "Foreach: Cannot convert from `%s' to `%s'".printf (element_type.to_string (), type_reference.to_string ()));
 332                         return false;
 333                 } else if (element_type.is_disposable () && element_type.value_owned && !type_reference.value_owned) {
 334                         error = true;
 335                         Report.error (source_reference, "Foreach: Invalid assignment from owned expression to unowned variable");
 336                         return false;
 337                 }
 338
 339                 return true;
 340         }
 341
 342         bool check_without_iterator (CodeContext context, DataType collection_type, DataType element_type) {
 343                 // analyze element type
 344                 if (type_reference == null) {
 345                         // var type
 346                         type_reference = element_type.copy ();
 347                 } else if (!element_type.compatible (type_reference)) {
 348                         error = true;
 349                         Report.error (source_reference, "Foreach: Cannot convert from `%s' to `%s'".printf (element_type.to_string (), type_reference.to_string ()));
 350                         return false;
 351                 }
 352
 353                 element_variable = new LocalVariable (type_reference, variable_name, null, source_reference);
 354
 355                 body.scope.add (variable_name, element_variable);
 356
 357                 body.add_local_variable (element_variable);
 358                 element_variable.active = true;
 359                 element_variable.checked = true;
 360
 361                 // analyze body
 362                 owner = context.analyzer.current_symbol.scope;
 363                 context.analyzer.current_symbol = this;
 364
 365                 // call add_local_variable to check for shadowed variable
 366                 add_local_variable (element_variable);
 367                 remove_local_variable (element_variable);
 368
 369                 body.check (context);
 370
 371                 foreach (LocalVariable local in get_local_variables ()) {
 372                         local.active = false;
 373                 }
 374
 375                 context.analyzer.current_symbol = context.analyzer.current_symbol.parent_symbol;
 376
 377                 collection_variable = new LocalVariable (collection_type, "%s_collection".printf (variable_name));
 378
 379                 add_local_variable (collection_variable);
 380                 collection_variable.active = true;
 381
 382                 add_error_types (collection.get_error_types ());
 383                 add_error_types (body.get_error_types ());
 384
 385                 return !error;
 386         }
 387
 388         public override void emit (CodeGenerator codegen) {
 389                 if (use_iterator) {
 390                         base.emit (codegen);
 391                         return;
 392                 }
 393
 394                 collection.emit (codegen);
 395                 codegen.visit_end_full_expression (collection);
 396
 397                 element_variable.active = true;
 398                 collection_variable.active = true;
 399                 if (iterator_variable != null) {
 400                         iterator_variable.active = true;
 401                 }
 402
 403                 codegen.visit_foreach_statement (this);
 404         }
 405
 406         public override void get_defined_variables (Collection<LocalVariable> collection) {
 407                 collection.add (element_variable);
 408         }
 409 }