Compiler Friendly Tail Recursion + Tail Recursion Checking in ATS

Question

What is the best way to check that a function has been tail call optimized in ATS? (So far I have been running "top" to see if memory usage is constant)

As a follow up: Say you have a complex tail-recursive function that the compiler has failed to TCO, is there a way to re-write it in a more compiler friendly way? Or in such a way to force the compiler to attempt TCO?

Answer 1

There is a peculiar way to do it in ATS2.

Say you have

fnx foo(...) = bar(...)
and bar(...) = ...bar...

If the body of bar contains a non-tail-recursive call to bar, then the C compiler is to complain with an error message.

Things become a lot more challenging when (linear) streams are involved. A seemingly non-tail-recursive function can run without concern of stack overflow because it essentially saves its stack on heap (and then frees it): This is a place where ATS really shines!