Composing "initial style" interpreter with final one

[femtomc]

Hi all!

I'm attempting to compose interpreters written in different styles.

One of my interpreters is a CPS interpreter - so I construct a Jaxpr for a function before transforming it (I'm calling this "initial style" after the nomenclature in higher order primitives). My interpreter then iterates over the equations, doing the right thing.

Now, I have another interpreter (imagine that it's a state-like interpreter - like harvest in Oryx). This interpreter has its own Trace, Tracer, Context, etc (okay to call this "final style"?)

Now, I'd like to be able to use these interpreters compositionally, in any order. The primitives and semantics for these interpreter don't overlap - so I expect application to be commutative.

One problem that occurs is that, if I have literal values in my function, I think that my first interpreter (the CPS interpreter) will partially evaluate bind calls e.g.

def foo():
    v = tag(0.3, "v")
    q = my_other_primitive(some_func, v)
    return q

In my first interpreter, there's not a "main trace" for bind to lookup, or associated tracers to full_raise - so my fallback pattern for handling tag in my first (CPS) interpreter likely just partially evaluates out the primitive. Then, if I try and run my second interpreter - there's no primitives for it to handle - so its semantics are removed.

Has anyone figured out how to handle this? I sort of want to prevent bind partial evaluation in my interpreter which doesn't use Trace or Tracers.

Edit: secondary Q -- how do "final style" interpreters process_primitive for things like tag(0.3, "v") (?) e.g. 0.3 is not a tracer. So at some level, an interpreter needs to be raising literals to the currently activate Trace right?

[femtomc]

Re — I thought about this today and I think the correct way to do this is to write an interpreter which gets access to the trace, and lifts arguments to tracer type, and then calls bind internally as it iterates over equations in the Jaxpr.

I think I can even do exotic things like CPS in this idiom.

[femtomc]

Related to #14647 - roughly the same question, but #14647 is easier to understand.

[femtomc]

Re -- I sort of solved this in #14647.