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Java > Open Source Codes > polyglot > frontend > VisitorPass


1 package polyglot.frontend;
2
3 import polyglot.ast.Node;
4 import polyglot.visit.NodeVisitor;
5 import polyglot.main.Report;
6 import polyglot.util.*;
7
8 /** A pass which runs a visitor. */
9 public class VisitorPass extends AbstractPass
10 {
11     Job job;
12     NodeVisitor v;
13
14     public VisitorPass(Pass.ID id, Job job) {
15     this(id, job, null);
16     }
17
18     public VisitorPass(Pass.ID id, Job job, NodeVisitor v) {
19         super(id);
20     this.job = job;
21     this.v = v;
22     }
23
24     public void visitor(NodeVisitor v) {
25     this.v = v;
26     }
27
28     public NodeVisitor visitor() {
29     return v;
30     }
31
32     public boolean run() {
33     Node ast = job.ast();
34
35     if (ast == null) {
36         throw new InternalCompilerError("Null AST: did the parser run?");
37     }
38
39         NodeVisitor v_ = v.begin();
40
41         if (v_ != null) {
42         ErrorQueue q = job.compiler().errorQueue();
43         int nErrsBefore = q.errorCount();
44
45             if (Report.should_report(Report.frontend, 3))
46                 Report.report(3, "Running " + v_ + " on " + ast);
47
48             ast = ast.visit(v_);
49             v_.finish(ast);
50
51             /*
52             // if the ast did not change, there no need to stop even if there
53             // are errors
54             if (ast == job.ast()) {
55                 return true;
56             }
57             */
58
59             int nErrsAfter = q.errorCount();
60
61             job.ast(ast);
62
63             return (nErrsBefore == nErrsAfter);
64             // because, if they're equal, no new errors occurred,
65 // so the run was successful.
66 }
67
68         return false;
69     }
70
71     public String JavaDoc toString() {
72     return id.toString();
73     }
74 }
75
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