Re: using MISC (post 1987 Forth hardware) opcodes


Adam Warner wrote:

We agree I did not provide a good enough example to support my claim. This
one should be bulletproof: You have a reason to trace though a deep
tree-like data structure. Mechanically this involves pushing paths you
still need to travel onto a stack every time you branch within the tree.
Recursion makes this mechanical process invisible.

That's not a problem. All you have to do is to use a threaded tree.

See: http://datastructures.itgo.com/trees/tbt.htm

An environment with six cell stacks cannot traverse this data structure
(without implementing userspace stacks out of heap memory). The stack is
blown around point 7 (earlier if there is already data on the return stack).

Or without altering the data structure and using a threaded tree.

A six cell environmental dependency is simply too low for general purpose
programming tasks. Whoever is willing to concede this (by highlighting a
specialised embedded environment) should beware of claiming that such a
restricted environment is also easier to program.

Regards,
Adam

I fail to see how such an enviornment is "restricted". As Jeff pointed
out
one can always implement "stacks in memory" if that's what someone
REALLY wants/needs to do. He did that on the F21 in order to support
an ANS Forth. But is that how you want your stacks to GENERALLY
be made? If I can have a MUCH faster hardware stack and then on
occassion use an in-memory stack (or be more thoughtfull on my
data structure choice) how am I at a disadvantage from using an
in-memory stack all of the time?

Regards,

John M. Drake

.

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