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1 package jfun.parsec;
2
3 final class OrParser extends Parser {
4 private final Parser[] alternatives;
5
6 OrParser(String  n, Parser[] alternatives) {
7 super(n);
8 this.alternatives = alternatives;
9 }
10
11 boolean apply(ParseContext ctxt) {
12 final Object ustate = ctxt.getUserState();
13 final Object ret = ctxt.getReturn();
14 final int at = ctxt.getAt();
15 final int step = ctxt.getStep();
16 final AbstractParsecError error = ctxt.getError();
17 AbstractParsecError err = error;
18 int err_at = -1;
19 int err_pos = -1;
20 int err_step = -1;
21 for(int i=0; i<alternatives.length; i++){
22 final Parser p1 = alternatives[i];
23 if(p1.parse(ctxt)) return true;
24 if(ctxt.hasException()) return false;
25 if(ctxt.getError().getIndex() > err_pos){
26 err_at = ctxt.getAt();
27 err_pos = ctxt.getError().getIndex();
28 err_step = ctxt.getStep();
29 err = AbstractParsecError.mergeError(err, ctxt.getError());
30 }
31 ctxt.set(step, at, ret, ustate, error);
32 }
33 ctxt.setAt(err_step, err_at);
34 ctxt.setError(err);
35 return false;
36 }
37
38 }
39 |
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