[piemonkey]

As a researcher that is currently working on implementing and improving existing PPLs, I'm very curious: what is your specific use-case that you have in mind for recursive queries?

[eli_gottlieb]

Honestly, I'd like to be able to try out some of the old social-reasoning demos from forestdb. It's not really a high-priority thing; it just bugs me that there were working languages for doing this (Church) and now there's basically just Anglican.

[wkv]

If you're interested in social reasoning and nested inference models, there's some examples of how they're implemented in WebPPL here: http://agentmodels.org/chapters/7-multi-agent.html. I think many of the reasoning examples from forestdb that are currently written in Church could be translated into WebPPL in a fairly straightforward manner using the same structure as the agentmodels examples.

[YeGoblynQueenne]

>> what is your specific use-case that you have in mind for recursive queries?

They probably want to run a recursive query.

(sorry)

[posterboy]

I never liked this approach to recursion, as in google's joke search correction for recursion, because recursion is a form of progressive iteration, not reiteration.

[YeGoblynQueenne]

Recursion is frequently used as progressive iteration, but it can go further than that.

Typical example, a factorial function, in Erlang:

  factorial(N) -> 
	factorial(N,1).

  factorial(0, F) -> F;
  factorial(N, F) -> 
	factorial(N-1, N*F).

It's strange to read that as iteration. Instead it feels natural to describe it as composition from parts that are of the same kind as the whole.

[posterboy]

of course that is some kind of iteration because tail recursion is isomorphic to loops and that N-1 sure looks like a while(--N)

[YeGoblynQueenne]

I'm not sure I know what "isomorphic" means in this context.

For sure, (tail) recursion places a pointer to a function on the stack while a loop is a conditional jump. They're not the same thing. I think the similarity between n-1 and --n is a red herring, here.