@Adám this website sir: abrudz.github.io/lb/apl

@chaugiang Oh, OK. You're welcome, but I actually just built on top of ground work made by @ngn.

@Adám, hi mate, yesterday I tried some tutorials in tryapl.org, and today my application for using Dyalog is approved. I tried to download RIDE github.com/Dyalog/ride/releases/tag/v4.2.3432. But I can not connect : i.imgur.com/jRJpD0k.png. Could you please take a look, I am using Ubuntu

@user563568 it is worked now, thank you a lot!

)about

@A__ You can evaluate a single line of APL by typing it into chat prefixed by ⍞←. Use ⎕← instead for boxed display and multi-line results and use ⋄ instead to silence the first statement. Use ] to call user commands, including ]help ⍣ for help on a glyph etc. Do not use markdown, but fixed-width (4 initial spaces) is fine. Commands: )lb for language bar, )docs for full documentation, )ref for PDF reference card, )idioms for idiom list.

@user563568 Thanks for helping chaugiang.

@DyalogAPL For example:

⍞←2+3+4

@Adám 9

@chaugiang Further from the tutorials on TryAPL, the lessons I gave in this chat room may interest you. Also, check out the bot's profile page, as it has lots of useful links. Oh, and while you may not be able to finish it, try the competition!

@Adám Thank you a lot for your help!

@chaugiang Do you want me to teach you more keyboard mnemonics?

@Adám, hi mate, I always try my best first because I am do not want to take someone's time, but if you have any special tips, I would love to know.

@chaugiang Very considerate of you, but it is part of my job. Anyway, you have ⍺ and ⍵ on a and w because they look alike. ⌊ is on f for floor, etc. etc.:

Is there a nicer way to express (f X)g f Y than (f⊣)g(f⊢)? This mentions f twice and I bet there's an idiom I am overlooking.

@Adám "all the way to the right"? — Genius. ;-)

@Adám I will save it in my mind, thank you so much!

@TorstenGrust nicer=shorter? (f⊣)g∘f⊢ is -1 byte, or you could do ⊃g/f¨X Y if X and Y allow that

also: g∘f⍨∘f⍨

@TorstenGrust g⍨∘f∘⍨f still mentions f twice. What you need is a new operator scheduled for Dyalog 18.0. It is called Over, and will probably get the symbol ⍥. The definition of g⍥f is exactly that. Meanwhile, you can define it as Ö←{(⍵⍵ ⍺)⍺⍺ ⍵⍵ ⍵}

@ngn ninja'd

@TorstenGrust You could actually find it on APLcart.

Gah, g⍨∘f∘⍨f has a typo. Should be g⍨∘f⍨∘f of course.

@ngn Thanks. Here, shaving bytes wouldn't be as much of a concern. It is more about clarity and intent. We're not comparing X and Y but their f-values. I was looking for a form that mentions f once.

@ngn Relatedly, a benefit of g⍨∘f⍨∘h over g∘f⍨∘h⍨ is the the left function of f and h (i.e. f) is applied to the left argument while the right function (i.e. h) is applied to the right argument. This is known (to Marshall and me, anyway) as "split-compose".

@TorstenGrust Exactly, you're applying "g over the f-values" or "g over f"

@TorstenGrust This pattern occurs all-over, once you learn to spot it. ⌈⍥≢ and <⍥| and ⍳⍥CaseFold etc. etc.

Oh, and I like ,⍥⊂. This is the same as {⍺ ⍵}.

@ngn Why would X and Y not allow that? The only case I can think of is a DECF and a complex number, in which case I'm wondering what you're doing anyway.

@Adám it might be part of a larger train where X and Y are functions

@Adám Yes, that's what I was after, I guess.

It's a prevalent pattern, for sure. Haskell has similar combinators (e.g., comparing) and it'd be a great addition to the APL vocabulary.

Cool. Thanks.

@ngn Good point.

Can someone explain to me what ⊥∘1 does?

@Adám {(⊣+×)/1,⌽0@1⊢⍵}

@dzaima Uh, OK. And in plain English?

@Adám except the obvious literal translation of the base conversion, i don't expect there to be anything much better than the literal translation of that function

@dzaima Ah, I should say "for Boolean vector arguments"

@Adám number of trailing ones, plus one if that's not the arguments length?

@dzaima Like in: (⊢⌽⍨1-=∘' '⊥1)Dm Right justify matrix Dm

@Adám Is that missing a ∘

@H.PWiz Oh, you're right, that's not a proper train. Will fix.

No, perhaps it should be (⊢⌽⍨1-1⊥⍨=∘' ')

Yup.

@Adám thanks, i hate it

@yiyus Welcome to The Orchard! Ready for some APL to complement your K knowledge?