Re: [Bug-apl] Monadic form of ↓

[Juergen Sauermann]

Hi Elias, I believe ↓ for 1↓ is too trivial to be useful. Unoccupied variants of APL primitives (like monadic ↓ or monadic =) are a very scarce resource that we should not use for trivial things. /// Jürgen On 10/09/2017 11:06 AM, Elias Mårtenson wrote: I was thinking about the usefulness of a monadic ↓ in terms of the new regexp feature. In the current version, when using subexpressions, the return value is always 1+the number of subexpressions, where the first one is always the full matched string. Monadic ↓ would be a neat way of dropping that part. In any case, my point is that monadic ↓ should do something useful. I guess split is one such useful thing. In GNU APL, I'd use ⊂⍤1 to achieve Split. Is that the most efficient way? Regards, Elias On 9 October 2017 at 16:58, Jay Foad <jay.f...@gmail.com> wrote: On 9 October 2017 at 04:56, Elias Mårtenson <loke...@gmail.com> wrote: Currently, monadic ↑ acts as if it was called dyadically with 1 as its left argument, That's not quite true:       ⍴⍴1↑'ABC' 1       ⍴⍴↑'ABC' 0 while monadic ↓ raises a VALENCE ERROR. In almost every single case where I have used ↓, it has been in the form 1↓X. Is there a reason why the monadic form is not allowed? FYI in Dyalog APL monadic ↓ is Split:       ↓3 3⍴⎕A ┌───┬───┬───┐ │ABC│DEF│GHI│ └───┴───┴───┘ I believe this came from STSC's NARS. Jay.