Re: Need some help understanding array definitions

Ed wrote:
"Elizabeth D Rather" <erather@xxxxxxxxx> wrote in message
news:AbidnWWvVJTSUM_VnZ2dnUVZ_qPinZ2d@xxxxxxxxxxxxxxxx
....
Presumably there is. Both major forth vendors have it in
their Windows product, albeit implemented in different ways.
Checkout R-ALLOC and R-BUF in SwiftForth.
Those words address specific issues regarding building stack frames for
Windows and DLL calls, and I'm sure MPE's equivalents address the same
need. That's a far cry from saying "Forth needs..." which implies a
general requirement in ordinary programming.

The guts of an implementation -- particularly for Windows, which has a
very specific set of problems -- will present special challenges. We
hope that by providing the tools for making the calls in a reasonably
programmer-friendly way we can avoid the necessity for doing these
things in application code.

Ok, since I'm not allowed to use the phrase "what forth needs"
I'll state it differently. I see advantages in this technique beyond
Windows.

Small targets may not have ALLOCATE or local buffers. If they
need a small temp buffer and can't do it the way Marcel suggested
because the compiler isn't resident, then this may be an alternative.

Since it takes less resources to implement and run than the
"Standard" methods currently on offer, it might have a greater
appeal.

Does it have limitations - yes, it's limited by the amount of free
space available on the return stack at any given time. On small
systems that could be quite small. Does that make it useless?
Users can judge for themselves.

I spend most of my life in small systems. We don't have ALLOCATE or local buffers, and never felt the lack. We *do* have "small temporary buffers": typically defined in terms of PAD, which resides in the otherwise unused space below the data stack. Using PAD is far safer than using the Return Stack, and requires *no* additional resources.

It's in the Standard, which also guarantees that no system functions use it, so it's a free application resource.

Cheers,
Elizabeth

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