Aha, I suspected as much, but being so new to the language I thought I would ask here to be sure. Thank you so much for your work on GNU APL. I still don't know exactly how or where I'll use APL, but I am enjoying how it directs one to think about problem-solving.
-Russ On Fri, 27 Nov 2020 at 05:42, Dr. Jürgen Sauermann <mail@jürgen-sauermann.de> wrote: > Hi Russ, > > welcome to APL. And welcome to bug-apl@gnu.org. The latter is a moderated > list, so please subscribe to > it because otherwise each of your emails will require (manual) approval by > myself. > > Back to your question, ⍸ is definitely not a standard APL primitive. My > only source of information about Dyalog APL, > the book with the title *Mastering Dyalog APL - **A Complete Introduction > to Dyalog APL*, seems not to mention it > either. > > I am somewhat reluctant when it comes to introducing non-standard APL > functions into GNU APL. In my > opinion, which is certainly arguable, non-standard extensions of APL may > lure APL programmers into > writing non-standard APL programs, which in turen undermines and even > contradicts the principles of > free software. > > For a non-standard extension to make it into APL, the extension has to > smoothly integrate into APL. One > of the rare examples where this was the case was monadic ⍳ with vector > arguments adopted from > Dyalog APL. That extension was sort of filling a rather arbitrary gap in > standard APL, making APL > more consistent than it was before. > > Some other extension in Dyalog did not make it into GNU APL because IMHO > the additional benefit that > they provided was not worth the incompatibility that every non-standard > extension unavoidably creates. > > I cannot judge to which kind of extensions ⍸ belongs since I do not know > what it actually does. I will consider > any opinions posted on bug-apl@gnu.org, though. > > Best Regards, > Jürgen > > > > On 11/26/20 11:15 PM, Russtopia wrote: > > Hi, newbie to APL so my sincere apologies in advance if this is incorrect, > an FAQ, or by design (intentionally not implemented). > > Dyalog APL appears to support monadic ⍸ (underscore-iota) primitive as a > 'where' function, eg. > > b ← 0 0 1 1 0 > ⍸b > 3 4 > > ..whereas GNU APL considers the ⍸ as an invalid symbol (SYNTAX ERROR) > > Equivalent seems to be > b / ⍳⍴ b > 3 4 > > .. just wondering if this is a Dyalog non-standard and if GNU APL plans to > implement it. > > Thanks, > -Russ > > >
