Line data    Source code

       1              : /* valawhilestatement.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 while iteration statement in the source code.
      27              :  */
      28         3074 : public class Vala.WhileStatement : Loop, Statement {
      29              :         /**
      30              :          * Creates a new while statement.
      31              :          *
      32              :          * @param condition         loop condition
      33              :          * @param body              loop body
      34              :          * @param source_reference  reference to source code
      35              :          * @return                  newly created while statement
      36              :          */
      37        29472 :         public WhileStatement (Expression condition, Block body, SourceReference? source_reference = null) {
      38         9824 :                 base (condition, body, source_reference);
      39              :         }
      40              : 
      41         8710 :         public override void accept (CodeVisitor visitor) {
      42         8710 :                 visitor.visit_while_statement (this);
      43              :         }
      44              : 
      45         8710 :         public override void accept_children (CodeVisitor visitor) {
      46         8710 :                 condition.accept (visitor);
      47              : 
      48         8710 :                 visitor.visit_end_full_expression (condition);
      49              : 
      50         8710 :                 body.accept (visitor);
      51              :         }
      52              : 
      53         9140 :         public override bool check (CodeContext context) {
      54         9140 :                 if (checked) {
      55            0 :                         return !error;
      56              :                 }
      57              : 
      58         9140 :                 checked = true;
      59              : 
      60              :                 // convert to simple loop
      61              : 
      62         9140 :                 if (condition.is_always_true ()) {
      63              :                         // do not generate if block if condition is always true
      64        18226 :                 } else if (condition.is_always_false ()) {
      65              :                         // do not generate if block if condition is always false
      66            2 :                         body.insert_statement (0, new BreakStatement (condition.source_reference));
      67              :                 } else {
      68         9112 :                         var if_condition = new UnaryExpression (UnaryOperator.LOGICAL_NEGATION, condition, condition.source_reference);
      69         9112 :                         var true_block = new Block (condition.source_reference);
      70         9112 :                         true_block.add_statement (new BreakStatement (condition.source_reference));
      71         9112 :                         var if_stmt = new IfStatement (if_condition, true_block, null, condition.source_reference);
      72         9112 :                         body.insert_statement (0, if_stmt);
      73              :                 }
      74              : 
      75         9140 :                 var loop = new LoopStatement (body, source_reference);
      76              : 
      77         9140 :                 unowned Block parent_block = (Block) parent_node;
      78         9140 :                 parent_block.replace_statement (this, loop);
      79              : 
      80         9140 :                 if (!loop.check (context)) {
      81            0 :                         error = true;
      82              :                 }
      83              : 
      84         9140 :                 return !error;
      85              :         }
      86              : }
      87              :