private static Nfa rule()
{
int num = 0;
NfaPair nfaPair = Alloc.NewNfaPair();
Nfa nfa;
Nfa end;
if (MakeNfa.spec.current_token == Tokens.AT_BOL)
{
num |= 1;
MakeNfa.gen.Advance();
MakeNfa.expr(nfaPair);
nfa = Alloc.NewNfa(MakeNfa.spec);
nfa.Edge = MakeNfa.spec.BOL;
nfa.Next = nfaPair.start;
end = nfaPair.end;
}
else
{
MakeNfa.expr(nfaPair);
nfa = nfaPair.start;
end = nfaPair.end;
}
if (Tokens.AT_EOL == MakeNfa.spec.current_token)
{
MakeNfa.gen.Advance();
NfaPair nfaPair2 = Alloc.NewNLPair(MakeNfa.spec);
end.Next = Alloc.NewNfa(MakeNfa.spec);
Nfa next = end.Next;
next.Next = nfaPair2.start;
next.Sibling = Alloc.NewNfa(MakeNfa.spec);
next.Sibling.Edge = MakeNfa.spec.EOF;
next.Sibling.Next = nfaPair2.end;
end = nfaPair2.end;
num |= 2;
}
if (end == null)
{
Error.ParseError(Errors.ZERO, MakeNfa.gen.InputFilePath, MakeNfa.input.line_number);
}
end.SetAccept(MakeNfa.gen.packAccept());
end.SetAnchor(num);
return(nfa);
}
/*
* Function: rule
* Description: Recursive descent regular expression parser.
*/
private static Nfa rule()
{
NfaPair pair;
Nfa start = null;
Nfa end = null;
int anchor = Spec.NONE;
#if DESCENT_DEBUG
Utility.enter("rule", spec.lexeme, spec.current_token);
#endif
pair = Alloc.NewNfaPair();
if (Gen.AT_BOL == spec.current_token)
{
anchor = anchor | Spec.START;
gen.Advance();
expr(pair);
start = Alloc.NewNfa(spec);
start.SetEdge(spec.BOL);
start.SetNext(pair.start);
end = pair.end;
}
else
{
expr(pair);
start = pair.start;
end = pair.end;
}
if (Gen.AT_EOL == spec.current_token)
{
gen.Advance();
NfaPair nlpair = Alloc.NewNLPair(spec);
end.SetNext(Alloc.NewNfa(spec));
Nfa enext = end.GetNext();
enext.SetNext(nlpair.start);
enext.SetSib(Alloc.NewNfa(spec));
enext.GetSib().SetEdge(spec.EOF);
enext.GetSib().SetNext(nlpair.end);
end = nlpair.end;
anchor = anchor | Spec.END;
}
/* check for null rules */
if (end == null)
{
Error.parse_error(Error.E_ZERO, input.line_number);
}
/* Handle end of regular expression */
end.SetAccept(gen.packAccept());
end.SetAnchor(anchor);
#if DESCENT_DEBUG
Utility.leave("rule", spec.lexeme, spec.current_token);
#endif
return(start);
}