@kentpitman Yes, good. One caveat is that, in the absence of hardcore unpredictable Lisp compiler optimizations, Lisp stack frames (and therefore things like unwinding) are much simpler than C. In Lisp "as she is spoke" [1], without optimization, doing e.g. evaluation of a polynomial at a point involves a bunch of function calls, period. In C it is a bunch of register operations. So the stack is wildly different between the two languages. Common optimizations will, you might say, make the Lisp evaluation more like the C evaluation, which then affects stack winding, so they've created a problem for themselves, now haven't they. 😉 [1] https://en.wikipedia.org/wiki/English_as_She_Is_Spoke @vnikolov @screwlisp