vala/valaexpressionstatement.vala

   1 /* valaexpressionstatement.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  * A code statement that evaluates a given expression. The value computed by the
  26  * expression, if any, is discarded.
  27  */
  28 public class Vala.ExpressionStatement : CodeNode, Statement {
  29         /**
  30          * Specifies the expression to evaluate.
  31          */
  32         public Expression expression {
  33                 get {
  34                         return _expression;
  35                 }
  36                 set {
  37                         _expression = value;
  38                         _expression.parent_node = this;
  39                 }
  40         }
  41
  42         private Expression _expression;
  43
  44         /**
  45          * Creates a new expression statement.
  46          *
  47          * @param expression        expression to evaluate
  48          * @param source_reference  reference to source code
  49          * @return                  newly created expression statement
  50          */
  51         public ExpressionStatement (Expression expression, SourceReference? source_reference = null) {
  52                 this.source_reference = source_reference;
  53                 this.expression = expression;
  54         }
  55
  56         public override void accept (CodeVisitor visitor) {
  57                 visitor.visit_expression_statement (this);
  58         }
  59
  60         public override void accept_children (CodeVisitor visitor) {
  61                 expression.accept (visitor);
  62         }
  63
  64         public override void replace_expression (Expression old_node, Expression new_node) {
  65                 if (expression == old_node) {
  66                         expression = new_node;
  67                 }
  68         }
  69
  70         public override bool check (CodeContext context) {
  71                 if (checked) {
  72                         return !error;
  73                 }
  74
  75                 checked = true;
  76
  77                 if (!expression.check (context)) {
  78                         // ignore inner error
  79                         error = true;
  80                         return false;
  81                 }
  82
  83                 add_error_types (expression.get_error_types ());
  84
  85                 return !error;
  86         }
  87
  88         public override void emit (CodeGenerator codegen) {
  89                 expression.emit (codegen);
  90
  91                 codegen.visit_expression_statement (this);
  92         }
  93
  94         public override void get_defined_variables (Collection<Variable> collection) {
  95                 expression.get_defined_variables (collection);
  96         }
  97
  98         public override void get_used_variables (Collection<Variable> collection) {
  99                 expression.get_used_variables (collection);
 100         }
 101 }