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Java > Open Source Codes > jfun > parsec > IfElseParser


1 /**
2  *
3  */
4 package jfun.parsec;
5
6 final class IfElseParser<R, C> extends Parser<R> {
7   private final Parser<? extends R> no;
8
9   private final Parser<C> p;
10
11   private final ToParser<? super C, R> yes;
12
13   IfElseParser(String JavaDoc n, Parser<? extends R> no, Parser<C> p, ToParser<? super C, R> yes) {
14     super(n);
15     this.no = no;
16     this.p = p;
17     this.yes = yes;
18   }
19
20   boolean apply(final ParseContext ctxt, final int look_ahead) {
21     final Object JavaDoc ustate = ctxt.getUserState();
22     final Object JavaDoc ret = ctxt.getReturn();
23     final int step = ctxt.getStep();
24     final int at = ctxt.getAt();
25     final AbstractParsecError error = ctxt.getError();
26     if (p.parse(ctxt))
27       return yes.toParser(p.getReturn(ctxt)).parse(ctxt);
28     return ParserInternals.recover(look_ahead, no, ctxt, step, at, ret, ustate, error);
29   }
30
31   boolean apply(final ParseContext ctxt) {
32     return apply(ctxt, 1);
33   }
34 }
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