Roger’s post speculating on Ken Iverson’s favourite APL expression reminded me that one of the delegates at Dyalog ’14 conducted a quick survey to find the most popular primitive (thanks to Alex Weiner for taking the initiative here!). His findings are reproduced below:
⍠ ⍟ * ⎕
⌽ ¨ ⍎
⍺ ∇ ≢ ← ⊃ ⊢ ⍬
⍉ , ∊ ⍋ ∘ ∧ ⍲ ⊥ ⌈
Unfortunately there were no reasons given…is it because it’s a shape that’s pleasing to the eye, a really nifty piece of functionality or something more esoteric?
As for me, it’s easy – my favourite is the Log glyph (
⍟). Not for a technical reason, although it performs a very useful function, nor due to its rather pleasing visual symmetry, but rather because of the way I was introduced to it. An APL virgin when I joined Dyalog 20 months ago, my first exercise was to familiarise myself with APL’s “beautiful squiggles”. When it came to the Log glyph I asked one of my colleagues a question and they dictated a line of APL to me to experiment with. As soon as they referred to
⍟ by its informal name of “splat” that was it, I was entranced. Any language that is so powerful, so concise and yet can make adults have passionate discussions involving the word “splat” has got me for life.