[Jprogramming] i. (2 2 $ 1 2 3 4)

[Erling Hellenäs]

I made it to learn FParsec, a parser, and more F#. I also used it in 
discussions about some features in J. It is fully useful as lambda 
expressions in F# and as an n-dimensional array class in F# with some 
pretty cool features. However, I do not intend to support it or develop 
it further. /Erling

On 2017-12-13 18:05, 'Bo Jacoby' via Programming wrote:
> The file:///C:/Users/Admin/Downloads/JWithATwistReferenceManual.pdf describes a new language, JWithATwist, but what problem is this language supposed so solve?
> Thanks.
> Bo.
>
>      Den 17:12 onsdag den 13. december 2017 skrev Erling Hellenäs <erling at erlinghellenas.se>:
>   
>
>   Hi all !
>
> It seems some related info did not make it into my blog and it is not
> needed in my manual. My tweets about this are advertently cryptic:
>
> -I found some interesting features of the real #J dyadic rank operator.
>
> -Let's say the rank is zero and the argument is empty, how do you find
> the resulting type and shape?
>
> -Nothing can not be scalar, which can be executed to find the rank, can it?
>
> -If you execute the verb on a scalar default object, what do you do if
> you get an error? Which rank and type will you use?
>
> More clearly:
>
> I have found that J determines the type and shape of the result when
> both arguments of the dyadic array operation helper program are empty by
> executing the verb against default objects of both arguments. If the
> result  is an error, J hides this error. The result then gets another
> rank than it should. The rank is then not consistent with the rank
> obtained when the arguments are not empty.
>
> This means that if you have a theory of how rank works, the theory will
> be falsified by some of the results you get, which means your
> understanding will most probably be fuzzy. You have to test all cases in
> the terminal to verify that it indeed works when one or the other
> argument, or both, are empty.
>
> According to my notes, this is such a case:
>
>      $(i.0) (2 1$ =)"1 0 [i.0
> 0
>      $(i.1) (2 1$ =)"1 0 [i.1
> 1 2 1
>
> Cheers,
>
> Erling Hellenäs
>
>
> Den 2017-12-13 kl. 16:24, skrev Erling Hellenäs:
>> This blogpost also contains related information.
>> https://erlhelinfotech.wordpress.com/2016/08/17/jwithatwist-scalar-operations/
>>
>>
>> /Erling
>>
>>
>> Den 2017-12-13 kl. 15:46, skrev Erling Hellenäs:
>>> It seems you didn't read the parts of my manual I referenced. /Erling
>>>
>>>
>>> Den 2017-12-13 kl. 14:39, skrev Raul Miller:
>>>> On Wed, Dec 13, 2017 at 3:46 AM, Erling Hellenäs
>>>> <erling at erlinghellenas.se> wrote:
>>>>> I doubt you can find reasonably accurate descriptions of this
>>>>> functionality
>>>>> (these four helper programs) anywhere else.
>>>> This suggests to me that you have not read
>>>>
>>>> http://www.jsoftware.com/help/dictionary/dictb.htm
>>>> nor
>>>> http://www.jsoftware.com/help/dictionary/dicta.htm
>>>>
>>>> I am surprised how many people have not read the reference manual -
>>>> not just in the J community but among technical people in general.
>>>>
>>>> I really don't know what to make of this.
>>>>
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