⎕←⍴⍬

@TessellatingHeckler
0

⎕←⍴'WORD'[⍬]

@TessellatingHeckler
0

⎕←⍬≡'WORD'[⍬]

@TessellatingHeckler
0

How do they not match? What else can be shape 0?

seriously speaking, 'WORD'[⍬] is an empty array of characters, you can test that by doing ⊃'WORD'[⍬], which gives a space - the "default character"

⍬ is an empty array of numbers, so ⊃⍬ is 0

I personally don't like the behavior though

⊃⍬ being .. unbox? disclose? first?

@TessellatingHeckler monadic ⊃ is first. It'll pick the first element of the array

@TessellatingHeckler the first item of the empty array, here that being the prototype. You can think of empty arrays as secretly having a single element in them, inaccessible by many things.

:|

ok, I guess that makes some behaviour align somewhere else

so, thanks for explaining :)

empty character array answers my question of how they don't match, I didn't realise that could be a thing, since I've only heard of Zilde

@TessellatingHeckler you can have empty arrays of arbitrary things - 0⍴⊂thing

who says APL doesn't have a type system

@TessellatingHeckler the usual reasoning is that it gives some default cases, i.e. if you've got an array of equal length arrays, if the outer arrays length is 0 it might still be good to know what would've been the size of the inner arrays. imo it just brings way too much unnecessary complexity

⎕← ⊃ 0⍴ ⊂'hello' (0 (0 (0 2)))

@dzaima
┌─────┬───────────┐
│     │┌─┬───────┐│
│     ││0│┌─┬───┐││
│     ││ ││0│0 0│││
│     ││ │└─┴───┘││
│     │└─┴───────┘│
└─────┴───────────┘

w.. what

@TessellatingHeckler i'd think what's usually said is that APL doesn't have a static type system, as APL definitely has an overly annoying dynamic type system (well, as far as the distinction between variables of functions, arrays & operators is concerned, which is none, until you're just away from executing a line and everything goes wrong)

⎕← 0⍴ ⊂'hello' (0 (0 (0 2)))

@TessellatingHeckler

oh; in TryAPL that renders a blank space the height of the invisible data

how is it picking the 0 0 0 2 out after reshaping it so they don't exist anymore

@TessellatingHeckler there is an element in the array, it just isn't counted in its shape, tally, etc.

⎕← ⊃ {⎕←1 2,⍵,'!'}¨ 0⍴⊂'¨ also sees the prototype, which can easily break non-functional code very often'(0(0 2 3))

@dzaima
┌─┬─┬────────────────────────────────────────────────────────────────────────────────┬─────────┬─┐
│1│2│                                                                                │┌─┬─────┐│!│
│ │ │                                                                                ││0│0 0 0││ │
│ │ │                                                                                │└─┴─────┘│ │
└─┴─┴────────────────────────────────────────────────────────────────────────────────┴─────────┴─┘

"WELL WHAT CHANCE DOES THAT GIVE ME?" - Brian

⎕←⊃0⍴⊂'AAA'

@TessellatingHeckler

that neither gives a space, nor 'AAA'

so it's not as simple as "the thing zero-reshaped is the prototype of the empty array returned"

@TessellatingHeckler that does give 3 spaces, but it's hard to see:

⎕← ⎕UCS ⊃0⍴⊂'AAA'

@dzaima
32 32 32

oh that's three spaces; I did space match

@TessellatingHeckler god that's a confusing sentence, but that definition should include that numbers are converted to 0s and chars to spaces (and other types result in nonce errors:)

⎕← ⊃0⍴⊂⎕NS⍬

@dzaima
NONCE ERROR

@dzaima sorry, can't easily type APL characters; ' '≡

what's NONCE in this context?

can't be cryptographic "number used once"

@dzaima TIL. Never got that error before

@J.Sallé I didn't either before Adám let me know

i guess copying from the network usage log works :|

NONCE has a meaning in the UK, and it's not polite; I was at least expecting it to stand for something technical

it just means "not implemented"; I hit it a lot when typing random stuff in not knowing what I'm doing