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Java > Open Source Codes > com > caucho > quercus > expr > CharAtExpr


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  *
23  * Free Software Foundation, Inc.
24  * 59 Temple Place, Suite 330
25  * Boston, MA 02111-1307 USA
26  *
27  * @author Scott Ferguson
28  */

29
30 package com.caucho.quercus.expr;
31
32 import com.caucho.quercus.Location;
33 import com.caucho.quercus.env.Env;
34 import com.caucho.quercus.env.Value;
35 import com.caucho.util.L10N;
36
37 /**
38  * Represents the character at expression
39  */

40 public class CharAtExpr extends AbstractVarExpr {
41   private static final L10N L = new L10N(CharAtExpr.class);
42
43   protected final Expr _objExpr;
44   protected final Expr _indexExpr;
45
46   public CharAtExpr(Location location, Expr objExpr, Expr indexExpr)
47   {
48     super(location);
49     _objExpr = objExpr;
50     _indexExpr = indexExpr;
51   }
52   
53   public CharAtExpr(Expr objExpr, Expr indexExpr)
54   {
55     _objExpr = objExpr;
56     _indexExpr = indexExpr;
57   }
58   
59   /**
60    * Evaluates the expression.
61    *
62    * @param env the calling environment.
63    *
64    * @return the expression value.
65    */

66   public Value eval(Env env)
67   {
68     Value obj = _objExpr.eval(env);
69
70     return obj.charValueAt(_indexExpr.evalLong(env));
71   }
72   
73   /**
74    * Evaluates the expression as an assignment.
75    *
76    * @param env the calling environment.
77    *
78    * @return the expression value.
79    */

80   public void evalAssign(Env env, Value value)
81   {
82     Value obj = _objExpr.eval(env);
83
84     Value result = obj.setCharValueAt(_indexExpr.evalLong(env), value.toString());
85
86     _objExpr.evalAssign(env, result);
87   }
88   
89   /**
90    * Evaluates the expression.
91    *
92    * @param env the calling environment.
93    *
94    * @return the expression value.
95    */

96   public void evalUnset(Env env)
97   {
98     throw new UnsupportedOperationException JavaDoc();
99   }
100   
101   /**
102    * Evaluates the expression.
103    *
104    * @param env the calling environment.
105    *
106    * @return the expression value.
107    */

108   public Value evalArg(Env env)
109   {
110     return eval(env);
111   }
112   
113   /**
114    * Evaluates the expression.
115    *
116    * @param env the calling environment.
117    *
118    * @return the expression value.
119    */

120   public Value evalRef(Env env)
121   {
122     return eval(env);
123   }
124
125   public String JavaDoc toString()
126   {
127     return _objExpr + "{" + _indexExpr + "}";
128   }
129 }
130
131
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