[kazinator]

The funny thing is, I originally didn't intend the TXR pattern language to be recursive. It needed functional decomposition (pattern functions) to break up a big pattern match into simpler units. When those were implemented, I realized after the fact, hey we have a push-down automaton that can now grok recursive grammars.

I don't see why we would want to rule out a pattern function invoking itself (directly, or through intermediaries); if that hurts, then just don't do that.

(Though I understand that there are languages deliberately designed without unbounded loops or recursion, for justifiable reasons.)

[js8]

I found in practice that arbitrary recursion depth is (even on languages with formal recursive grammar) very rarely needed. And where it's needed it can probably be implemented as a primitive in the language (map total function over all the nodes) that can do a similar thing.