1 package org.drools.semantics.python;
2
3 /*
4 $Id: ExprVisitor.java,v 1.3 2003/03/25 19:47:32 tdiesler Exp $
5
6 Copyright 2002 (C) The Werken Company. All Rights Reserved.
7
8 Redistribution and use of this software and associated documentation
9 ("Software"), with or without modification, are permitted provided
10 that the following conditions are met:
11
12 1. Redistributions of source code must retain copyright
13 statements and notices. Redistributions must also contain a
14 copy of this document.
15
16 2. Redistributions in binary form must reproduce the
17 above copyright notice, this list of conditions and the
18 following disclaimer in the documentation and/or other
19 materials provided with the distribution.
20
21 3. The name "drools" must not be used to endorse or promote
22 products derived from this Software without prior written
23 permission of The Werken Company. For written permission,
24 please contact bob@werken.com.
25
26 4. Products derived from this Software may not be called "drools"
27 nor may "drools" appear in their names without prior written
28 permission of The Werken Company. "drools" is a registered
29 trademark of The Werken Company.
30
31 5. Due credit should be given to The Werken Company.
32 (http://drools.werken.com/).
33
34 THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS
35 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
36 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
37 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
38 THE WERKEN COMPANY OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
39 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
40 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
41 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
42 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
43 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
44 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
45 OF THE POSSIBILITY OF SUCH DAMAGE.
46
47 */
48 /*
49 (c) Copyright 2001, 2002 Tonic Software, Inc.
50 All Rights Reserved
51 */
52
53 import org.python.parser.SimpleNode;
54 import org.python.parser.Visitor;
55 import org.python.parser.ast.Name;
56
57 import java.util.HashSet;
58 import java.util.Set;
59
60 /*** Visits nodes in a Jython parse tree to extract the individual expression criteria.
61 *
62 * @author <a href="martin@tonic.com">Martin Chilvers</a>
63 * @author <a href="bob@werken.com">bob mcwhirter</a>
64 * @author <a href="mailto:christiaan@dacelo.nl">Christiaan ten Klooster</a>
65 */
66 public class ExprVisitor extends Visitor
67 {
68 // ------------------------------------------------------------
69 // Instance members
70 // ------------------------------------------------------------
71
72 /*** List of the variables as we parse an expression. */
73 private Set variables;
74
75 // ------------------------------------------------------------
76 // Constructors
77 // ------------------------------------------------------------
78
79 /*** Construct.
80 */
81 ExprVisitor()
82 {
83 // intentionally left blank.
84 }
85
86 // ------------------------------------------------------------
87 // Instance methods
88 // ------------------------------------------------------------
89
90 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
91 // org.python.parser.Visitor
92 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
93
94 /*** Visite the node.
95 *
96 * @param node The node.
97 *
98 * @return Set of variable names.
99 *
100 * @throws Exception If an error occurs while traversing.
101 */
102 public Object eval_input(SimpleNode node) throws Exception
103 {
104 variables = new HashSet();
105
106 traverse( node );
107
108 return variables;
109 }
110
111 /*** Visit a Name node.
112 *
113 * @param Name The node.
114 *
115 * @return The node.
116 *
117 * @throws Exception If an error occurs while traversing.
118 */
119 public Object visitName(Name node) throws Exception
120 {
121 variables.add( ((Name)node).id );
122
123 return node;
124 }
125
126 }
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