private static Sexp parseCharacterClass(String pattern, Sexp sexp) {
Matcher matcher = Pattern.compile("(.*)(.\\-.)(.*)").matcher(pattern);
if (matcher.matches()) {
String[] range = matcher.group(2).split("-");
parseCharacterClass(matcher.group(1), sexp);
sexp.add(new Sexp(RANGE).add(literal(range[0])).add(literal(range[1])));
parseCharacterClass(matcher.group(3), sexp);
} else if (!pattern.isEmpty()) {
for (String token : pattern.split("")) {
sexp.add(literal(token));
}
}
return sexp;
}
private static Sexp intersection(Sexp lhs, Sexp rhs) {
Sexp intersectionSexp = new Sexp(INTERSECTION).add(lhs);
if (rhs.first().equals(INTERSECTION)) {
intersectionSexp.addAll(ArrayUtils.remove(rhs.getValues().toArray(), 0));
} else {
intersectionSexp.add(rhs);
}
return intersectionSexp;
}
private static Sexp quantifyRhs(Sexp sexp, Quantifier quantifier) {
Sexp quantifierSexp = null;
if (sexp.first() != null && sexp.first().equals(UNION)) {
quantifierSexp = sexp.add(quantify((Sexp) sexp.removeLast(), quantifier));
} else {
quantifierSexp = quantify(sexp, quantifier);
}
return quantifierSexp;
}
private static Sexp union(Sexp lhs, Sexp... rhs) {
if (lhs == null) {
return union(rhs[0], (Sexp[]) ArrayUtils.remove(rhs, 0));
} else if (ArrayUtils.isEmpty(rhs)) {
return lhs;
} else if (lhs.first() != null && lhs.first().equals(UNION)) {
for (Sexp sexp : rhs) {
lhs.add(sexp);
}
return lhs;
}
return new Sexp(UNION).add(lhs).addAll(rhs);
}
