Intersection of two regular expressions

Question

Im looking for function (PHP will be the best), which returns true whether exists string matches both regexpA and regexpB.

Example 1:

$regexpA = \'[0         


        

Answer 1

Theory.

Java library.

Usage:

/**
 * @return true if the two regexes will never both match a given string
 */
public boolean isRegexOrthogonal( String regex1, String regex2 ) {
   Automaton automaton1 = new RegExp(regex1).toAutomaton();
   Automaton automaton2 = new RegExp(regex2).toAutomaton();
   return automaton1.intersection(automaton2).isEmpty();
}