CATCH restores stack state incorrectly

[alexshpilkin]

The code

: TEST-T   1 THROW ;
: TEST   3 ['] TEST-T CATCH ;
TEST . . DEPTH . CR

prints 1 3 0 on latest Gforth and VFX, but 1 1 0 on latest pForth git. I can’t point to a particular sentence in the standard, but I’d expect that if the code inside the CATCH didn’t touch an item on the stack, that item would be unaffected by the THROW.

[philburk]

The THROW docs at: https://forth-standard.org/standard/exception/THROW are pretty clear about all the stacks being restored to their depth when catch was called. So pForth has a bug.

I need to check to make sure the float stack is also handled properly.

[philburk]

I have tried twice to fix this and it is not easy. PForth does not implement CATCH THROW like a normal Forth. CATCH actually calls the inner interpreter, this is pfCatch(). Fixing this would require some major refactoring, That is too risky for the 2.0.0 release. So I am punting this to a later version.