Re: "Back & Forth" - Local variables

On 09-01-2025 13:42, dxf wrote:

There is no guarantee that a saved interpreter pointer on the
stack is an execution token.

Nope - in ANS-Forth it is listed as:
nest-sys; definition calls; implementation dependent
So - that's obvious. But in 4tH it works out. And defining it as >R works out as well. BTW, I've tested the thing - and it holds up.
I got my work cut out for a next episode! On co-routines! ;-)
Hans Bezemer
BTW, I've heard there are implementations where nest-sys aren't even on the return stack. The standard seems to confirm this:
return stack:  A stack that _MAY_BE_ used for program execution nesting, do-loop execution, temporary storage, and other purposes.
.. and sorry to spoil the fun, but what we're doing here is illegal anyways:
"A program shall _NOT_ access values on the return stack (using R@, R>, 2R@ or 2R>) that it _DID_NOT_ place there using >R or 2>R;"
In other words: your mileage may (be) very, very illegal.
Hans Bezemer