Raul, I think it is so useful it should be available immediately on starting J!
> On 25 Oct 2022, at 15:54, Raul Miller <rauldmil...@gmail.com> wrote:
>
> Actually, thinking about this, a series of related essays might be useful.
>
> I'm not quite sure how they should be labeled. But using J to build
> expression-like results to illustrate concepts seems like a general
> and illustrative technique for beginners. (Though of course it's also
> useful for addons, like the math/calculus package.)
>
> Thanks,
>
> --
> Raul
>
>> On Tue, Oct 25, 2022 at 10:49 AM Raul Miller <rauldmil...@gmail.com> wrote:
>>
>> Given the character of this work, it might be more useful as an essay,
>> rather than an addon.
>>
>> That said, it could also be rewritten to be more compact. For example:
>>
>> bracket=: 3 :0
>> if. 1=#y=.":y do. y else. '(',y,')' end.
>> )
>>
>> instance=: 1 :0
>> m,'_',bracket y
>> :
>> (bracket x),'_',m,'_',bracket y
>> )
>>
>> instances=: 3 :0
>> (y,'_z_')=:(y)=:y instance
>> EMPTY
>> )
>>
>> linstances=: 3 :0
>> instances y [ instances y,'l'
>> )
>>
>> linstances"0 'fghi'
>>
>> (Though, also, here, the first and =: declaration could be made to be
>> more compact -- using the new {{ }} explicit form they could be made
>> single line declarations with possibly improved clarity.)
>>
>> Thanks,
>>
>> --
>> Raul
>>
>>> On Tue, Oct 25, 2022 at 9:55 AM chris burke <cbu...@jsoftware.com> wrote:
>>>
>>> I think this is Simon Garland's fgh script, which used to be
>>> distributed in system/packages/misc/fgh.ijs. For example:
>>>
>>> load '~temp/fgh.ijs'
>>>
>>> 0 f g h 1
>>> 0 _f_ (g_ (h_ 1))
>>>
>>>
>>> 0 (f g h) 1
>>> (0 _f_ 1) _g_ (0 _h_ 1)
>>>
>>> The script is below. Perhaps someone could check it, and then we put
>>> it in the addons?
>>>
>>> -----------------------
>>>
>>> NB. fgh.ijs
>>> NB.
>>> NB. displays calling sequence for simple J expressions, where:
>>> NB.
>>> NB. f_ monadic f
>>> NB. _f_ dyadic f
>>> NB. _fI_ dyadic inverse of f etc..
>>> NB.
>>> NB. e.g.
>>> NB. f g h 0
>>> NB. (f g h) 0
>>> NB. f&g 0
>>> NB. f&.g 0
>>> NB. 0 f g 1
>>> NB. f/1 2 3
>>>
>>> bracket=: 3 : 0
>>> if. (1=$,y=.":y) do. y
>>> else. '(',y,')' end.
>>> )
>>>
>>> f=: 3 : 0
>>> 'f_ ',bracket y
>>> :
>>> (bracket x),' _f_ ',bracket y
>>> )
>>>
>>> g=: 3 : 0
>>> 'g_ ',bracket y
>>> :
>>> (bracket x),' _g_ ',bracket y
>>> )
>>>
>>> h=: 3 : 0
>>> 'h_ ',bracket y
>>> :
>>> (bracket x),' _h_ ',bracket y
>>> )
>>>
>>> i=: 3 : 0
>>> 'i_ ',bracket y
>>> :
>>> (bracket x),' _i_ ',bracket y
>>> )
>>>
>>> fI=: 3 : 0
>>> 'fI_ ',bracket y
>>> :
>>> (bracket x),' _fI_ ',bracket y
>>> )
>>>
>>> gI=: 3 : 0
>>> 'gI_ ',bracket y
>>> :
>>> (bracket x),' _gI_ ',bracket y
>>> )
>>>
>>> hI=: 3 : 0
>>> 'hI_ ',bracket y
>>> :
>>> (bracket x),' _hI_ ',bracket y
>>> )
>>>
>>> iI=: 3 : 0
>>> 'iI_ ',bracket y
>>> :
>>> (bracket x),' _iI_ ',bracket y
>>> )
>>>
>>> NB. definitions in z locale:
>>> f_z_=: f_fgh_ :. fI_fgh_
>>> g_z_=: g_fgh_ :. gI_fgh_
>>> h_z_=: h_fgh_ :. hI_fgh_
>>> i_z_=: i_fgh_ :. iI_fgh_
>>>
>>> On Sun, Oct 23, 2022 at 10:45 PM Richard Donovan <rsdono...@hotmail.com>
>>> wrote:
>>>>
>>>> Many years ago (J4 or J6) I remember there was a function that showed how
>>>> hooks and trains etc were expanded, using such output as x _f_ g_ y etc
>>>> (where _f_ indicated dyad etc). Does anyone know of this and whether it
>>>> still exists?
>>>>
>>>> Thanks in advance
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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