@Adám In course.dyalog.com/broken-keyboard-problems, ToUpper ← {(⎕A,' ')[⍺⍳⍵]} should be ToUpper ← {(⎕A,' ')[alph⍳⍵]}

I added ngn/apl to omnibar, though I don't understand what the identity element operator does, it got a ??? both in the call pattern and in the description

also don't know where to link since apparently no documentation exists? for ≈ I thought I'd link to the line of APL code where it is defined

also not sure what dialect to do next, ideas? might do kap

@RubenVerg It sets the identity element for a function (well, makes a new function with that identity element), so for example +⍁5/ ⍳0 is 5.

@Adám Was looking at the reduced family tree and I think the overall picture is muddied by some questionable links. APL\360→J makes no sense to me. NARS→APL2 I don't know about, and I'd expect APL\360→APL2 instead. I'd also probably cut SHARP→Dyalog as the influences that can't be explained via J are pretty small.

@Marshall oh, I thought it was to somehow get the identity element. thanks, added!

What are the options, if any, for running dyalog apl on an iphone?

@RubenVerg Definitely a confusing one. The syntax should include both valences, like ⊙ in NARS (it's more relevant to the dyadic case if anything, since that's the one reduction uses).

@RubenVerg Some small errors with dyadic Grade: it's listed as a monadic function, and omnibar says dzaima/APL has it when it's shown as NYI in the docs and gives an error in the interpreter.

Likewise for dyadic Transpose in dzaima/APL.

thanks for spotting those! I'll fix them tomorrow

why does this fail with a LENGTH error: (⊢⌿⍨2|⍳⍤≢)1 1 0 0. I am simply trying to filter to the 1st and 3rd element.

@Jonah ⌿ is a bit strange, so you need ⊢⍤⌿ instead of it.

I was trying to use replicate, what am I doing wrong?

@Adám ie, I thought ⊢ was 1 1 0 0 and that ⌿⍨ was saying "compress that using the mask 1 0 1 0"

oh i see i need parens to do what i wanted: (⊢(⌿⍨)2|⍳⍤≢)1 1 0 0

Otherwise it gets interpreted as a 2-train instead of a 3-train (I think)

@Jonah That'll do it too, but the issue is actually that ⌿ prefers being Reduce rather than Replicate, and thus it'll be reduce whenever a function is to its left. You had ⊢ there. I suggested adding ⊢⍤ to its left, because ⍤ isn't a function, but ( isn't a function either, so both methods work.

@Adám " ⌿ prefers being Reduce rather than Replicate" What is the general parsing principle at play here, if any? In J, (]#~2|i.@#) automatically parses as a 3 train (but # in J is only a verb, it doesn't double as an operator/adverb). So is the problem here uniquely related to Replicate, or generally that if something can be interpreted as a fn or operator, it gets parsed as an operator first? or something else?

@Jonah apl.wiki/hybrid

@Adám ty. do you consider this a design flaw?

yes