Re: [Jchat] J "like-wow"s?

There are many in my memory (but sometimes not as clear as they once were) having started being wowed by them more than 50 years ago One that I proudly remember was a response from The Hui that he was wowed by my response to a forum question asking how to calculate the distance from origin o

Re: [Jchat] J "like-wow"s?

Yes, sorry: TranX is transitive extension, TranClo, transitive closure. On 2020.03.15 20:42:39, you, the extraordinary Devon McCormick, spake thus: > Maybe "TranClo" is transitive closure? > > On Sun, Mar 15, 2020 at 6:28 PM Nollaig MacKenzie > wrote: > > > I've always liked these (originally

Re: [Jchat] J "like-wow"s? the inverse

require'convert' hfd 123 Also dfh... I mean, yes, J has nice words for the calculations. But hexadecimal has library support also... Thanks, -- Raul On Sun, Mar 15, 2020 at 3:38 PM Gilles Kirouac wrote: > ok, audience, after some effort, we now have a hexadecimal to decimal > function.

Re: [Jchat] J "like-wow"s?

Maybe "TranClo" is transitive closure? On Sun, Mar 15, 2020 at 6:28 PM Nollaig MacKenzie wrote: > I've always liked these (originally from > a paper by Perlis and Rugaber on APL idioms): > >TranX > +. +./ .*.~ >TranClo > TranX^:_ > > (The argument should be a square boolean matrix). > >

Re: [Jchat] J "like-wow"s?

I've always liked these (originally from a paper by Perlis and Rugaber on APL idioms): TranX +. +./ .*.~ TranClo TranX^:_ (The argument should be a square boolean matrix). On 2020.03.14 12:19:30, you, the extraordinary 'PMA' via Chat, spake thus: > > So I want to ask, could y'all sugges

Re: [Jchat] J "like-wow"s? the inverse

ok, audience, after some effort, we now have a hexadecimal to decimal function.   htd=:16&#.@:('0123456789ABCDEF'&i.)   htd 'FFF' 4095 Now we would like to have a decimal to hexadecimal one, to "reverse the operation". We could sit and work hard to write it. BUT wait, we don't need to!! We ask J

Re: [Jchat] J "like-wow"s?

Since Dijkstra features prominently in your essay, you may be interested in *A Letter from Dijkstra on APL .* On Sun, Mar 15, 2020 at 9:14 AM Devon McCormick wrote: > The "Array Thinking" page is at > https://code.jsoftware.com/wiki/Array_Th

Re: [Jchat] J "like-wow"s?

The "Array Thinking" page is at https://code.jsoftware.com/wiki/Array_Thinking but it still needs some work on formatting. On Sun, Mar 15, 2020 at 12:12 PM Devon McCormick wrote: > Yes - on the "Array Thinking" page I referred to a similar note you sent a > while back and I quote from the Perlis

Re: [Jchat] J "like-wow"s?

Yes - on the "Array Thinking" page I referred to a similar note you sent a while back and I quote from the Perlis paper. The explicit reference to the APL expression on the Ken Iverson page (at https://en.wikipedia.org/wiki/Kenneth_E._Iverson#/media/File:APLparen.png) is nice, especially in its si

Re: [Jchat] J "like-wow"s?

Your one-liner on parentheses nesting has an ancient and honorable pedigree. See the Ken Iverson Wikipedia page (in the IBM (1960-1980) section) and the third paragraph of Alan Perlis's "*APL is more French than English*"

Re: [Jchat] J "like-wow"s?

There's this (adapted from my new "Array Thinking" page on the J wiki): NB. String from https://wiki.c2.com/?LispShowOffExamples string=. '(flet ((inside-p (obj) (lambda (d) (inside-p obj (ray-point ray d)' string,:' '-.~":'()' ([:+/\1 _1 0{~i.) stringNB. Example result (flet ((ins