How to generate strings by regexp in Scala

Question

Suppose there is a simple regular expression (only | and * are allowed). How would you create a stream of strings of any size (from smaller to larger) which match this regular expression in Scala?

Answer 1

Use Xeger. Even though it's Java and not Scala, you should have no problem using it with Scala.

In Java:

String regex = "[ab]{4,6}c";
Xeger generator = new Xeger(regex);
String result = generator.generate();
assert result.matches(regex);