oops except for the first times I used A and B, it should always have been B and A: result type A; A are data, B control
Am 23.02.21 um 21:36 schrieb Hauke Rehr: > At first, I wanted to state strong disagreement. > But wait. > I still do think the order is counterintuitive, > but now I think the way it’s defined is actually > better in terms of 'data' vs 'control'. > > Let me explain: > > Folds are a variation on / > There’s not much more to it. > The main advantage is: x doesn’t need to have the same > type/shape as an item of y > So a better example would show this. > > Say v takes an A-structure on the right and a B-structure > on the left. In a fold (x1 v (x2 v (x3 v (x4 v y)))) we > need x v y to return a B-structure. > But that looks more like those B-structures are data > and the A-structures control their being transformed by v > which is consistent with x to the left and y to the right > /and/ with the array processed item-by-item becoming this > very x and the initial value becoming y. > > So if at all, we’d need to spell the example > 1 2 3 4 ] F:. see_arg 7 > and have F:. work that way – which it does if you > introduce some ~ > 1 2 3 4 (] F:. see_arg~)~ 7 > (I hope that’s correct – these swappings are a bit confusing) > > I don’t think /that one/ will get much applause. > (I’d say let’s do it – but I don’t expect many to agree) > > Counterintuitive, but for a good reason. > > Am 23.02.21 um 21:01 schrieb Henry Rich: >> x is a 'control' input to the fold. >> >> Each item of y (and x if given) is a 'data' input to v. >> >> There's an end on't! >> >> Henry rich >> >> On 2/23/2021 2:46 PM, Brian Schott wrote: >>> I think I am in favor of Sergey's suggestion. In my excerpted J session >>> below I created a verb called test which has the traditional arguments x >>> and y to emphasize how I think of the placement of x and y. The x and >>> y in the >>> verb test are reversed relative to the x and y in see_arg. That's the >>> inconsistency. So, I guess I'm one of the 8 people using F: now. <grin> >>> >>> see_arg =: dyad : 0 >>> >>> echo x, y >>> >>> x + y >>> ) >>> test=: 4 : 'x ] F:. see_arg y' >>> test >>> 4 : 'x ] F:. see_arg y' >>> 7 test 1 2 3 4 >>> 1 7 >>> 2 8 >>> 3 10 >>> 4 13 >>> 8 10 13 17 >>> JVERSION >>> Engine: j902/j32/android >>> Release-a: commercial/2020-12-24T11:35:03 >>> Library: 9.02.08 >>> J Android: 1.4.12/9/28 >>> Platform: Android 32 (armeabi-v7a) >>> Installer: unknown >>> InstallPath: >>> /storage/emulated/0/Android/data/com.jsoftware.j.android/files >>> Contact: www.jsoftware.com >>> >>> (B=) >>> >>> On Sun, Feb 21, 2021, 1:53 PM 'Sergey' via Programming < >>> [email protected]> wrote: >>> >>>> Hi! >>>> >>>> I am glad that in version 9.02 verbs are now executed from right to >>>> left, >>>> which corresponds to the logic of J. >>>> >>>> However, in my opinion, the order of passing arguments to the right verb >>>> (see_arg in my example) >>>> also needs to be changed for the logic of J. >>>> >>>> see_arg =: dyad : 0 >>>> NB. See argument order >>>> echo x, y >>>> x + y >>>> ) >>>> >>>> Today: >>>> >>>> 7 ] F:. see_arg 1 2 3 4 >>>> >>>> 1 7 >>>> 2 8 >>>> 3 10 >>>> 4 13 >>>> 8 10 13 17 >>>> >>>> The proposed order is more logical: left ini value goes to left argument >>>> and right array values going to right argument of verb: >>>> >>>> 7 ] F:. see_arg 1 2 3 4 >>>> >>>> 7 1 >>>> 8 2 >>>> 10 3 >>>> 13 4 >>>> 8 10 13 17 >>>> >>>> Sergey. >>>> >>>> >>>> >>>> On Sun, 21 Feb 2021 07:28:44 -0600, Julian Fondren < >>>> [email protected]> wrote: >>>> >>>>> There's " https://code.jsoftware.com/wiki/Vocabulary/quotem >>>>> Common use #2, to make a constant verb out of a noun. >>>>> >>>>> (_."_)`2:`3:@.] i:2 >>>>> 2 3 _. 2 3 >>>> Hi Julian, >>>> >>>> thanks for the hint! This does exactly what I was looking for. >>>> >>>> Regards, >>>> >>>> Thomas >>>> ---------------------------------------------------------------------- >>>> 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 >> >> > -- ---------------------- mail written using NEO neo-layout.org ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
