Line data    Source code

       1              : /* valanullliteral.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              : using GLib;
      24              : 
      25              : /**
      26              :  * Represents a literal `null` in the source code.
      27              :  */
      28         1537 : public class Vala.NullLiteral : Literal {
      29              :         /**
      30              :          * Creates a new null literal.
      31              :          *
      32              :          * @param source reference to source code
      33              :          * @return       newly created null literal
      34              :          */
      35      1660658 :         public NullLiteral (SourceReference? source = null) {
      36       830329 :                 source_reference = source;
      37              :         }
      38              : 
      39      1572364 :         public override void accept (CodeVisitor visitor) {
      40      1572364 :                 visitor.visit_null_literal (this);
      41              : 
      42      1572364 :                 visitor.visit_expression (this);
      43              :         }
      44              : 
      45            3 :         public override string to_string () {
      46            3 :                 return "null";
      47              :         }
      48              : 
      49            0 :         public override bool is_pure () {
      50            0 :                 return true;
      51              :         }
      52              : 
      53       810659 :         public override bool check (CodeContext context) {
      54       810659 :                 if (checked) {
      55        42278 :                         return !error;
      56              :                 }
      57              : 
      58       768381 :                 checked = true;
      59              : 
      60       768381 :                 value_type = new NullType (source_reference);
      61              : 
      62       768381 :                 return !error;
      63              :         }
      64              : 
      65         6296 :         public override void emit (CodeGenerator codegen) {
      66         6296 :                 codegen.visit_null_literal (this);
      67              : 
      68         6296 :                 codegen.visit_expression (this);
      69              :         }
      70              : }