> Begin forwarded message:
>
> From: Louis de Forcrand <ol...@bluewin.ch>
> Subject: Re: [Bug-apl] ^C ATTENTION
> Date: 10 Oct 2015 02:03:22 CEST
> To: Juergen Sauermann <juergen.sauerm...@t-online.de>
>
> Jürgen,
>
> Sorry for the delay.
>
> If I declare a LIFE function for finding the next generation in the game of
> life:
>
> ∇
> [0] λ←LIFE ⍵
> [1] λ←⊃∨/1 ⍵∧3 4=+/+⌿¯1 0 1∘.⊖¯1 0 1⌽¨⊂⍵
> ∇
>
> and then call it on a matrix M:
>
> LIFE ⍣≡ M
>
> it should find the final state of M (if it exists!) after which it won’t
> change anymore when fed into LIFE (right?).
> The problem is when it never reaches a “static” state, then it won’t stop
> without intervention. This is where I’ve
> tried using ^C (pressing once, and pressing twice in a row), and neither
> seemed to halt the process.
> I imagine the primitive to modify is ⍣?
>
> PS: Gmane seems quite slow these days. Or is it on my side?
>
> Best of luck,
> ⊣ Louis
>
>> On 03 Oct 2015, at 12:21, Juergen Sauermann <juergen.sauerm...@t-online.de
>> <mailto:juergen.sauerm...@t-online.de>> wrote:
>>
>> Hi Louis,
>>
>> could you provide a concrete example?
>>
>> Some remarks on ^C in GNU APL. There are two levels: a single ^C (called
>> ATTENTION) and two ^C
>> within one second (called INTERRUPT).
>>
>> ATTENTION is primarily checked by the runtime parser at the end of the line.
>> This is to make
>> →N work nicely so that the interrupted line is finished before execution is
>> stopped.
>>
>> INTERRUPT is currently checked in printouts so that the display of long
>> values can be aborted.
>> In general INTERUPT has a potential of leaving behind an inconsistent
>> workspace and, if
>> checked to often, of performance impact. Therefore an example would be handy
>> so that I
>> can see which (and where) an operation could be stopped in a reasonable way.
>>
>> /// Jürgen
>>
>>
>> On 10/01/2015 10:26 PM, Louis de Forcrand wrote:
>>> I've noticed that CONTROL-C works quite well with
>>> multiple-line functions, but not nearly as well with
>>> programs that use ⍣ for example (one-liners).
>>> APL just seems to freeze, and with a little luck it
>>> stops and prints ATTENTION, while at other times
>>> it just doesn't seem to stop at all.
>>
>
