Feature Request: Lisp interpreter of Varjo function

[kchanqvq]

It would be nice if one can call Varjo function from lisp directly
to test its value on specific input.
This can be useful in several cases, including debugging, and
a automatic navigator I'm writing (my renderer uses distance field and
raymarching, the distance field function is written in Varjo but is also
needed by the navigator).

Currently I'm using my own adhoc code walker and setting symbol-function
for vari symbols that I encountered. Is there currently a systematic way to
do it, or do you have any idea how to do it "correctly"? I'm happy to help if I could.