Line data    Source code

       1              : /* valanulltype.vala
       2              :  *
       3              :  * Copyright (C) 2007-2010  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              : using GLib;
      24              : 
      25              : /**
      26              :  * The type of the null literal.
      27              :  */
      28         1423 : public class Vala.NullType : ReferenceType {
      29       819809 :         public NullType (SourceReference? source_reference = null) {
      30       819809 :                 base (null, source_reference);
      31       819809 :                 this.nullable = true;
      32              :         }
      33              : 
      34       612834 :         public override bool compatible (DataType target_type) {
      35       612834 :                 if (CodeContext.get ().experimental_non_null) {
      36         5647 :                         return target_type.nullable;
      37              :                 }
      38              : 
      39       607187 :                 if (!(target_type is PointerType) && (target_type is NullType || (target_type.type_symbol == null && !(target_type is GenericType)))) {
      40         4482 :                         return true;
      41              :                 }
      42              : 
      43              :                 /* null can be cast to any reference or array type or pointer type */
      44       603540 :                 if (target_type is GenericType ||
      45       595674 :                     target_type is PointerType ||
      46       577418 :                     target_type.nullable ||
      47          835 :                     target_type.type_symbol.has_attribute ("PointerType")) {
      48       601870 :                         return true;
      49              :                 }
      50              : 
      51          835 :                 if (target_type.type_symbol.is_reference_type () ||
      52           26 :                     target_type is ArrayType ||
      53           26 :                     target_type is DelegateType) {
      54       607187 :                         return true;
      55              :                 }
      56              : 
      57              :                 /* null is not compatible with any other type (i.e. value types) */
      58       612834 :                 return false;
      59              :         }
      60              : 
      61        51428 :         public override DataType copy () {
      62        51428 :                 return new NullType (source_reference);
      63              :         }
      64              : 
      65        10723 :         public override bool is_disposable () {
      66        10723 :                 return false;
      67              :         }
      68              : 
      69            2 :         public override string to_qualified_string (Scope? scope = null) {
      70            2 :                 return "null";
      71              :         }
      72              : }