/jEdit/tags/jedit-4-1-pre5/bsh/BSHForStatement.java
Java | 152 lines | 68 code | 23 blank | 61 comment | 12 complexity | 45ff1c90141df4057f124256d38b6a3a MD5 | raw file
Possible License(s): BSD-3-Clause, AGPL-1.0, Apache-2.0, LGPL-2.0, LGPL-3.0, GPL-2.0, CC-BY-SA-3.0, LGPL-2.1, GPL-3.0, MPL-2.0-no-copyleft-exception, IPL-1.0
1/*****************************************************************************
2 * *
3 * This file is part of the BeanShell Java Scripting distribution. *
4 * Documentation and updates may be found at http://www.beanshell.org/ *
5 * *
6 * Sun Public License Notice: *
7 * *
8 * The contents of this file are subject to the Sun Public License Version *
9 * 1.0 (the "License"); you may not use this file except in compliance with *
10 * the License. A copy of the License is available at http://www.sun.com *
11 * *
12 * The Original Code is BeanShell. The Initial Developer of the Original *
13 * Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
14 * (C) 2000. All Rights Reserved. *
15 * *
16 * GNU Public License Notice: *
17 * *
18 * Alternatively, the contents of this file may be used under the terms of *
19 * the GNU Lesser General Public License (the "LGPL"), in which case the *
20 * provisions of LGPL are applicable instead of those above. If you wish to *
21 * allow use of your version of this file only under the terms of the LGPL *
22 * and not to allow others to use your version of this file under the SPL, *
23 * indicate your decision by deleting the provisions above and replace *
24 * them with the notice and other provisions required by the LGPL. If you *
25 * do not delete the provisions above, a recipient may use your version of *
26 * this file under either the SPL or the LGPL. *
27 * *
28 * Patrick Niemeyer (pat@pat.net) *
29 * Author of Learning Java, O'Reilly & Associates *
30 * http://www.pat.net/~pat/ *
31 * *
32 *****************************************************************************/
33
34
35package bsh;
36
37/**
38 Implementation of the for(;;) statement.
39*/
40class BSHForStatement extends SimpleNode implements ParserConstants
41{
42 public boolean hasForInit;
43 public boolean hasExpression;
44 public boolean hasForUpdate;
45
46 private SimpleNode forInit;
47 private SimpleNode expression;
48 private SimpleNode forUpdate;
49 private SimpleNode statement;
50
51 private boolean parsed;
52
53 BSHForStatement(int id) { super(id); }
54
55 public Object eval(CallStack callstack , Interpreter interpreter)
56 throws EvalError
57 {
58 int i = 0;
59 if(hasForInit)
60 forInit = ((SimpleNode)jjtGetChild(i++));
61 if(hasExpression)
62 expression = ((SimpleNode)jjtGetChild(i++));
63 if(hasForUpdate)
64 forUpdate = ((SimpleNode)jjtGetChild(i++));
65 if(i < jjtGetNumChildren()) // should normally be
66 statement = ((SimpleNode)jjtGetChild(i));
67
68 NameSpace enclosingNameSpace= callstack.top();
69 BlockNameSpace forNameSpace = new BlockNameSpace( enclosingNameSpace );
70
71 /*
72 Note: some interesting things are going on here.
73
74 1) We swap instead of push... The primary mode of operation
75 acts like we are in the enclosing namespace... (super must be
76 preserved, etc.)
77
78 2) We do *not* call the body block eval with the namespace
79 override. Instead we allow it to create a second subordinate
80 BlockNameSpace child of the forNameSpace. Variable propogation
81 still works through the chain, but the block's child cleans the
82 state between iteration.
83 (which is correct Java behavior... see forscope4.bsh)
84 */
85
86 // put forNameSpace it on the top of the stack
87 // Note: it's important that there is only one exit point from this
88 // method so that we can swap back the namespace.
89 callstack.swap( forNameSpace );
90
91 // If we wanted untyped variables in the for-init to be local, instead
92 // of having side effects in the parent context of the for-loop we
93 // could setInitMode() here to capture them and make them local.
94 ///forNameSpace.setInitMode(true);
95
96 // Do the for init
97 if ( hasForInit )
98 forInit.eval( callstack, interpreter );
99
100 // If we had turned on init mode to capture untyped for-init vars
101 // and make them local to the for-loop scope we would turn it off here
102 //forNameSpace.setInitMode(false);
103
104 Object returnControl = Primitive.VOID;
105 while(true)
106 {
107 if ( hasExpression )
108 {
109 boolean cond = BSHIfStatement.evaluateCondition(
110 expression, callstack, interpreter );
111
112 if ( !cond )
113 break;
114 }
115
116 boolean breakout = false; // switch eats a multi-level break here?
117 if ( statement != null ) // not empty statement
118 {
119 // do *not* invoke special override for block... (see above)
120 Object ret = statement.eval( callstack, interpreter );
121
122 if (ret instanceof ReturnControl)
123 {
124 switch(((ReturnControl)ret).kind)
125 {
126 case RETURN:
127 returnControl = ret;
128 breakout = true;
129 break;
130
131 case CONTINUE:
132 break;
133
134 case BREAK:
135 breakout = true;
136 break;
137 }
138 }
139 }
140
141 if ( breakout )
142 break;
143
144 if ( hasForUpdate )
145 forUpdate.eval( callstack, interpreter );
146 }
147
148 callstack.swap( enclosingNameSpace ); // put it back
149 return returnControl;
150 }
151
152}