private Grammar ERI()
{
if (eof)
{
return(null);
}
SkipNewLine();
Grammar grammar;
switch (lookAhead)
{
case Sym.PERIOD:
grammar = new CONCATENATION();
match(Sym.PERIOD); grammar.addFirst(ERI()); grammar.addSecond(ERI());
break;
case Sym.OR:
grammar = new OR();
match(Sym.OR); grammar.addFirst(ERI()); grammar.addSecond(ERI());
break;
case Sym.QUESTION_MARK:
grammar = new QUESTION();
match(Sym.QUESTION_MARK); grammar.addFirst(ERI());
break;
case Sym.TIMES:
grammar = new Times();
match(Sym.TIMES); grammar.addFirst(ERI());
break;
case Sym.PLUS:
grammar = new Plus();
match(Sym.PLUS); grammar.addFirst(ERI());
break;
case Sym.OPEN_CB:
grammar = LEAF();
break;
case Sym.STRING:
grammar = LEAF();
break;
default:
grammar = null;
ERROR();
Sync();
break;
}
return(grammar);
}
