Re: QUIT and ABORT

On 2025-05-20 09:49, dxf wrote:

On 19/05/2025 8:52 pm, Ruvim wrote:

On 2025-05-18 18:27, dxf wrote:

On 18/05/2025 6:16 pm, Ruvim wrote:

...
Note that in `error` you don't transfer control to `(abort)` only in the case of `-56`.

>
I transfer control to (abort) except in the case of -56 where it passes to (quit).

>
Hence, `-56` is a special case in your implementation.

 No more special than what ANS did for -1 and -2 .

Anyway, ANS does not define any special *behavior* for `-56`, does it?
[...]

You interpret the reservation of `-56` for `quit` as a provision to make `quit` catchable.

 Correct.  I'm grateful for serious opponents as they do my homework for me.
If I had any concerns about a catchable QUIT beforehand, your posts have
resolved them.

I've seen no convincing rationale that QUIT should not have
the same entitlement as ABORT and ABORT" .

This train has long since left.

But catchable `quit` is not ANS Forth compliant. And your deviation in the behavior of `throw` is also not ANS compliant.

 That would be your interpretation.

Not just mine. Anyone who agrees with the following premise should agree with this interpretation.
In a standard system, any behavior that is not explicitly allowed by the standard (and can be detected by a standard program) is prohibited. In a standard program, any behavior that is not explicitly prohibited by the standard is allowed.
Therefore, on performing a standard program a Forth system is not allowed to produce any unspecified effect that can affect the behavior of the program.
NB: in ambiguous conditions the system is allowed to do whatever implementers prefer because it is explicitly specified; however, a standard program is not allowed to enter an ambiguous condition.
I also made these arguments on 2019-09-08 [1] and on 2020-02-06 [2].
[1] <https://groups.google.com/d/msg/comp.lang.forth/YorBW05PS0A/CMDd7XsrAwAJ>
[2] <https://groups.google.com/g/comp.lang.forth/c/HDhDvu3PQHI/m/F5akTJgqFwAJ>

You can resolve it for future standards by putting it to the committee.
 

For example, how it can be formulated?
--
Ruvim