Re: QUIT and ABORT

On 24/05/2025 7:20 pm, Ruvim wrote:

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?

But you agree the special behaviour is necessary for a system with
catchable QUIT where QUIT is executed but no exception frame exists?

Reasons to not generally define a special behaviour for -56 ...
a) only systems that want a catchable QUIT need it
b) not every system is capable of providing the special behaviour

[...]
 

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.

Just as ANS allowed ABORT and ABORT" to be catchable or not and the application
programmer had to factor that in, so must he do for QUIT.

...

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

 
For example, how it can be formulated?

It's unlikely a 'Request for Clarification' is applicable as ANS TC no longer
exists.  That leaves making a proposal reflecting the outcome that you want.