Tinkering around with a FRACTRAN library I wrote in...

Tinkering around with a FRACTRAN library I wrote in Common Lisp :^)

I was too lazy to add sequential functions, but it is possible if you assign a unique prime to each function (as it will permit only that function)

Prime numbers just happen to be a powerful way to express the concept of "distinct" objects. In this case, the "objects" are registers/memory addresses. Might try replacing primes with strings...