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1 package gnu.expr;
2 import gnu.bytecode.*;
3 import gnu.mapping.*;
4
5
9
10 public class TryExp extends Expression
11 {
12 Expression try_clause;
13
14 CatchClause catch_clauses;
15
16 Expression finally_clause;
17
18 public final CatchClause getCatchClauses () { return catch_clauses; }
19 public final void setCatchClauses (CatchClause catch_clauses)
20 {
21 this.catch_clauses = catch_clauses;
22 }
23
24 public TryExp (Expression try_clause, Expression finally_clause)
25 {
26 this.try_clause = try_clause;
27 this.finally_clause = finally_clause;
28 }
29
30 protected boolean mustCompile () { return catch_clauses != null; }
31
32 public void apply (CallContext ctx) throws Throwable 
33 {
34 if (catch_clauses != null)
35 throw new RuntimeException ("internal error - TryExp.eval called");
36 try
37 {
38 try_clause.apply(ctx);
39 ctx.runUntilDone();
40 }
41 catch (Throwable ex)
42 {
43 for (CatchClause clause = catch_clauses; clause != null;
44 clause = clause.next)
45 {
46 }
49 throw ex;
50 }
51 finally
52 {
53 finally_clause.eval(ctx);
54 }
55 }
56
57 public void compile (Compilation comp, Target target)
58 {
59 CodeAttr code = comp.getCode();
60 boolean has_finally = finally_clause != null;
61 Type result_type = target instanceof IgnoreTarget ? null
62 : getType();
63 Target ttarg;
64 if (result_type == null)
65 ttarg = Target.Ignore;
66 else if (result_type == Type.pointer_type)
67 ttarg = Target.pushObject;
68 else
69 ttarg = new StackTarget(result_type);
70 code.emitTryStart(has_finally, result_type);
71 try_clause.compileWithPosition(comp, ttarg);
72 code.emitTryEnd();
73
74 CatchClause catch_clause = catch_clauses;
75 for (; catch_clause != null; catch_clause = catch_clause.getNext())
76 {
77 catch_clause.compile(comp, ttarg);
78 }
79
80 if (finally_clause != null)
81 {
82 code.emitFinallyStart();
83 finally_clause.compileWithPosition(comp, Target.Ignore);
84 code.emitFinallyEnd();
85 }
86 code.emitTryCatchEnd();
87 if (result_type != null)
88 target.compileFromStack(comp, result_type);
89 }
90
91 protected Expression walk (ExpWalker walker)
92 {
93 return walker.walkTryExp(this);
94 }
95
96 protected void walkChildren(ExpWalker walker)
97 {
98 try_clause = walker.walk(try_clause);
99 CatchClause catch_clause = catch_clauses;
100 while (walker.exitValue == null && catch_clause != null)
101 {
102 walker.walk(catch_clause);
103 catch_clause = catch_clause.getNext();
104 }
105
106 if (walker.exitValue == null && finally_clause != null)
107 finally_clause =walker.walk( finally_clause);
108 }
109
110 public void print (OutPort ps)
111 {
112 ps.startLogicalBlock("(Try", ")", 2);
113 ps.writeSpaceFill();
114 try_clause.print(ps);
115 CatchClause catch_clause = catch_clauses;
116 for (; catch_clause != null; catch_clause = catch_clause.getNext())
117 {
118 catch_clause.print(ps);
119 }
120 if (finally_clause != null)
121 {
122 ps.writeSpaceLinear();
123 ps.print(" finally: ");
124 finally_clause.print(ps);
125 }
126 ps.endLogicalBlock(")");
127 }
128 }
129 |
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