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Java > Open Source Codes > jfun > parsec > TryParser


1 /**
2  *
3  */
4 package jfun.parsec;
5
6 final class TryParser<R> extends Parser<R> {
7   private final Parser<R> p;
8
9   private final Catch<? extends R> hdl;
10
11   TryParser(String JavaDoc n, Parser<R> p, Catch<? extends R> hdl) {
12     super(n);
13     this.p = p;
14     this.hdl = hdl;
15   }
16
17   boolean apply(final ParseContext ctxt) {
18     final AbstractParsecError err0 = ctxt.getError();
19     final boolean r = p.parse(ctxt);
20     if (!ctxt.hasException())
21       return r;
22     final Parser h = hdl.catchException(ctxt.getReturn(), ctxt.getError()
23         .getException());
24     ctxt.setError(err0);
25     return h.parse(ctxt);
26   }
27 }
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