> Regular Expressions to do not compose well. That is patently untrue. Regular expressions compose under a number of important mathematical operations, such as

> Regular Expressions to do not compose well. That is patently untrue. Regular expressions compose under a number of important mathematical operations, such as union, intersection and concatenation. If your PL supports string interpolation, it's trivial to compose them in these ways (well ok, maybe not intersection). Nobody says that your regex needs to be written as a single string.