@Uriel @KritixiLithos Advanced Stencil usage.

Can you grok it?

@Adám Quick question (not related with the stencil): what does + mean in DISPLAY?

@KritixiLithos It means that the simple array has multiple data types. E.g. 1 2 3,'abc' is a simple vector, but with both numeric and character data.

I was asking because I was trying to golf my submission for wheat wizard's parenthesis challenge

@KritixiLithos And?

I got 1∘⌽⍣{2::0⋄⍴⍎⊃,/'1',¨⍺}⊢')('['()'⍳⎕], but it is a bit too verbose

and I tried removing the quotes around the '1', but it errors out

@KritixiLithos Yes, because ⍎ can only take character data.

{2::0⋄⍴⍎⊃,/'1',¨⍺} checks if the parentheses are balanced or not

@KritixiLithos how about ⍎⍕1,¨⍺ ?

Ah thanks, that works

@KritixiLithos In most cases, ∊ is equivalent to ⊃,/ but ⍎ doesn't care about extra spaces, so you can just flatten-stringify with ⍕.

@KritixiLithos So ]display was telling you with the + that you had mixed numbers and characters.

@KritixiLithos Since the right operand to ⍣ is a function, you don't need the ⊢

@KritixiLithos Also, since this is clearly a tradfn body, you can remove the ∘

@Adám what does ⍺⍺ mean?

@Uriel left operand. E.g. if you wanted to define a cover for ¨ it would be each←{⍺⍺¨⍵}

@Adám why wouldn't a single ⍺ work?

@Uriel Because the dfn in ⌽{⍺¨⍵} doesn't have a left argument. the ⌽ will only apply to the result of the dfn. In other words, the curly braces cannot "catch" a function other than as operand. Functions take data as arguments while operators can take both data and functions as operands.

@Adám :thumbs up: I'm halfway across the 4july question, but my solution doesn't even resemble yours

@Uriel That's fine. Go ahead and post it (when you're done) anyway. So much better to have multiple APL approaches.

@Uriel This must be my most complicated explanation ever. Does it make any sense?

@Adám yea, it's detailed even more than my monolith answer

you practically explained about half of APL symbols

@Adám I think I might give it a bounty to give it more attention

@Uriel Cool.

If you think that explanation is detailed, take a look at this answer

@Adám So the tradfn knows that the 1⌽ is by itself one function, or does it interpret it any differently?

And btw, thanks for the tips

@TwiNight can't you change the answer to a tradfn and drop the ⎕←?

@KritixiLithos That's just how a function derived from ⍣ apply dyadically

X (f⍣g) Y sort of "binds" the X

So it does X f Y, then X f X f Y, etc.

@TwiNight amazing answer.

@KritixiLithos As I've explained here, I think tradfn body is a snippet rather than function

@KritixiLithos No, as TN said, f⍣g is a new ambivalent function, while A∘f⍣g is a new monadic function.

@Uriel You mean the algorithm or the explanation?

@KritixiLithos But as I responded, a snippet would not even prompt for input, but assume the variables already to have values, as stated by the author of the comment that TN linked to, in a post that that author linked to.

@TwiNight Mostly the fact that you wrote these. And mostly the algo.

@TwiNight So what exactly is your code? It sure looks like a tradfn body to me!

@TwiNight You can remove +.×1 0J1 and take input as 4-element vectors of xJy Complex numbers in Dyalog APL are the closest thing to tuples (which OP allowed). They are actually implemented as pairs of floats.

Hmm.. I thought those scripts can be interpreted directly

However, if function main(){} have to be counted in C, I don't see APL getting around ∇f∇

Or we can meta-post that

it's actually int main(){}, but yeah

Can you run Dyalog APL scripts from the command-line?

I know you can do dyalog workspace.the_extension_for_workspaces_I_forgot_what_it_was for workspaces, but that only enters the interactive session in the workspace

@TwiNight why not?

@TwiNight You can pipe into the session, but then you don't need ⎕← either: Try it online!

@KritixiLithos ^

@KritixiLithos .dws and if ⎕LX (Latent Expression) has a value in that workspace, the interpreter will do ⍎⎕LX automatically. You could also pipe in an expression to bootstrap.

@Adám That's how tio does it under the hood, right?

I suppose tio's wrapper can be an "interpreter" of a dialect of Dyalog where scripts like this can be run

@TwiNight No, TIO's Header-Code-Footer constitute the body of a :Namespace…:EndNamespacethat gets all its content copied to #.

@TwiNight However, the Input does get piped in like that.

@TwiNight Yes, and in the Input, you don't need ⎕← to output.

@Adám regarding codegolf.stackexchange.com/a/130123/65326, why is the +/ inside the parenthesis? shouldnt it come only after the !*! is applied?

@Uriel Because then it is an atop of an atop. Otherwise it becomes a left tine with the parens as the middle tine. Also, ⎕IO←1.

@Adám sorry, forgot to edit. atop? tine?

@Uriel atop: 2-train, f g; tine: one of the three parts of a fork, f g h

@Adám ogreat, thanks