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Java > Open Source Codes > de > gulden > util > javasource > jjt > JJTParserState


1 /* Generated By:JJTree: Do not edit this line. /tmp/make/beautyJ-1_1/src/beautyj/de/gulden/util/javasource/jjt/JJTParserState.java */
2
3 package de.gulden.util.javasource.jjt;
4
5 class JJTParserState {
6   private java.util.Stack JavaDoc nodes;
7   private java.util.Stack JavaDoc marks;
8
9   private int sp; // number of nodes on stack
10 private int mk; // current mark
11 private boolean node_created;
12
13   JJTParserState() {
14     nodes = new java.util.Stack JavaDoc();
15     marks = new java.util.Stack JavaDoc();
16     sp = 0;
17     mk = 0;
18   }
19
20   /* Determines whether the current node was actually closed and
21      pushed. This should only be called in the final user action of a
22      node scope. */
23   boolean nodeCreated() {
24     return node_created;
25   }
26
27   /* Call this to reinitialize the node stack. It is called
28      automatically by the parser's ReInit() method. */
29   void reset() {
30     nodes.removeAllElements();
31     marks.removeAllElements();
32     sp = 0;
33     mk = 0;
34   }
35
36   /* Returns the root node of the AST. It only makes sense to call
37      this after a successful parse. */
38   Node rootNode() {
39     return (Node)nodes.elementAt(0);
40   }
41
42   /* Pushes a node on to the stack. */
43   void pushNode(Node n) {
44     nodes.push(n);
45     ++sp;
46   }
47
48   /* Returns the node on the top of the stack, and remove it from the
49      stack. */
50   Node popNode() {
51     if (--sp < mk) {
52       mk = ((Integer JavaDoc)marks.pop()).intValue();
53     }
54     return (Node)nodes.pop();
55   }
56
57   /* Returns the node currently on the top of the stack. */
58   Node peekNode() {
59     return (Node)nodes.peek();
60   }
61
62   /* Returns the number of children on the stack in the current node
63      scope. */
64   int nodeArity() {
65     return sp - mk;
66   }
67
68
69   void clearNodeScope(Node n) {
70     while (sp > mk) {
71       popNode();
72     }
73     mk = ((Integer JavaDoc)marks.pop()).intValue();
74   }
75
76
77   void openNodeScope(Node n) {
78     marks.push(new Integer JavaDoc(mk));
79     mk = sp;
80     n.jjtOpen();
81   }
82
83
84   /* A definite node is constructed from a specified number of
85      children. That number of nodes are popped from the stack and
86      made the children of the definite node. Then the definite node
87      is pushed on to the stack. */
88   void closeNodeScope(Node n, int num) {
89     mk = ((Integer JavaDoc)marks.pop()).intValue();
90     while (num-- > 0) {
91       Node c = popNode();
92       c.jjtSetParent(n);
93       n.jjtAddChild(c, num);
94     }
95     n.jjtClose();
96     pushNode(n);
97     node_created = true;
98   }
99
100
101   /* A conditional node is constructed if its condition is true. All
102      the nodes that have been pushed since the node was opened are
103      made children of the the conditional node, which is then pushed
104      on to the stack. If the condition is false the node is not
105      constructed and they are left on the stack. */
106   void closeNodeScope(Node n, boolean condition) {
107     if (condition) {
108       int a = nodeArity();
109       mk = ((Integer JavaDoc)marks.pop()).intValue();
110       while (a-- > 0) {
111     Node c = popNode();
112     c.jjtSetParent(n);
113     n.jjtAddChild(c, a);
114       }
115       n.jjtClose();
116       pushNode(n);
117       node_created = true;
118     } else {
119       mk = ((Integer JavaDoc)marks.pop()).intValue();
120       node_created = false;
121     }
122   }
123 }
124
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