vala/valacastexpression.vala

   1 /* valacastexpression.vala
   2  *
   3  * Copyright (C) 2006-2009  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 Gee;
  24
  25 /**
  26  * Represents a type cast in the source code.
  27  */
  28 public class Vala.CastExpression : Expression {
  29         /**
  30          * The expression to be cast.
  31          */
  32         public Expression inner {
  33                 get {
  34                         return _inner;
  35                 }
  36                 set {
  37                         _inner = value;
  38                         _inner.parent_node = this;
  39                 }
  40         }
  41
  42         /**
  43          * The target type.
  44          */
  45         public DataType type_reference {
  46                 get { return _data_type; }
  47                 set {
  48                         _data_type = value;
  49                         _data_type.parent_node = this;
  50                 }
  51         }
  52
  53         /**
  54          * Checked casts return NULL instead of raising an error.
  55          */
  56         public bool is_silent_cast { get; set; }
  57
  58         private Expression _inner;
  59
  60         private DataType _data_type;
  61
  62         /**
  63          * Creates a new cast expression.
  64          *
  65          * @param inner expression to be cast
  66          * @param type  target type
  67          * @return      newly created cast expression
  68          */
  69         public CastExpression (Expression inner, DataType type_reference, SourceReference source_reference, bool is_silent_cast) {
  70                 this.type_reference = type_reference;
  71                 this.source_reference = source_reference;
  72                 this.is_silent_cast = is_silent_cast;
  73                 this.inner = inner;
  74         }
  75
  76         public override void accept (CodeVisitor visitor) {
  77                 inner.accept (visitor);
  78                 type_reference.accept (visitor);
  79
  80                 visitor.visit_cast_expression (this);
  81
  82                 visitor.visit_expression (this);
  83         }
  84
  85         public override void replace_expression (Expression old_node, Expression new_node) {
  86                 if (inner == old_node) {
  87                         inner = new_node;
  88                 }
  89         }
  90
  91         public override bool is_pure () {
  92                 return inner.is_pure ();
  93         }
  94
  95         public override void replace_type (DataType old_type, DataType new_type) {
  96                 if (type_reference == old_type) {
  97                         type_reference = new_type;
  98                 }
  99         }
 100
 101         public override bool check (SemanticAnalyzer analyzer) {
 102                 if (checked) {
 103                         return !error;
 104                 }
 105
 106                 checked = true;
 107
 108                 if (!inner.check (analyzer)) {
 109                         error = true;
 110                         return false;
 111                 }
 112
 113                 type_reference.check (analyzer);
 114
 115                 // FIXME: check whether cast is allowed
 116
 117                 value_type = type_reference;
 118                 value_type.value_owned = inner.value_type.value_owned;
 119
 120                 inner.target_type = inner.value_type.copy ();
 121
 122                 return !error;
 123         }
 124
 125         public override void get_defined_variables (Collection<LocalVariable> collection) {
 126                 inner.get_defined_variables (collection);
 127         }
 128
 129         public override void get_used_variables (Collection<LocalVariable> collection) {
 130                 inner.get_used_variables (collection);
 131         }
 132 }