User blog comment:12AbBa/A Function Part II/@comment-31040770-20190913164047/@comment-35470197-20190915125741

Hmm...? According to the OP, there are just two rules: the base rule and the recursion rule. The explanations outside the two rules are not general rules. Or does "Then" mean "In addition" in some dialect? If so, then I am just misunderstanding what the OP wrote.