Torsten Grust

(I too love Haskell, by the way ;-).

≢⍴42 → 0

A scalar is dimension-less and has rank 0. Vectors have rank 1.

Try ≢⍴⊃numbers to see that you have, indeed, extracted a scalar (with empty shape) from numbers.

@Nathan on the big screen in Elsinore!

Hello from Dyalog'19, Helsingør (Denmark).

"To infinity and beyond"

:-)

Thanks, @Adam.

I am floored, really.

It says "Phase II – Winning Professional Entrant" on the web page. I haven't heard anything yet, though.

Oh, looks like I'll travel to Denmark in September?!

{ e(x) | x ∊ X, p(x) } ≡ [ e x | x <- X, p x]

I also like the comprehension style: [ min (x-y) (y-z) | [x,y,z] <- chunksOf 3 A ]

This is practically all we use in my group to create written material.

I can highly recommend taking a look at it.

casual-effects.com/markdeep

In Markdeep, to be precise.

Thanks, I should know better. I create all of my lecture material and notes in Markdown. For years now.

Thanks, I'll make copies of this for future uses.

Urgh ;-)

`\` is the lambda

@Adám map (\[x,y,z] -> min (x-y) (y-z)) . chunksOf 3

{x y z←⍵⋄(x-y)⌊(z-y)}¨3,/ A is the Haskell version.

Thanks for the link.

@Adám 2000! Where do you source the upcoming entries from?

I fully agree regarding the utility of the construct. Have found myself counting the length of the input, instead. Not nice.

Ah, I see now.

⍬2⍴...? Useful!

select sum(t.x) from (values (null::int),(null),(null)) AS t(x); → null (not 0).

@PaulMansour Hi Paul. One detail: SQL's sum doesn't treat null as zero. null is ignored/skipped by almost all aggregate functions except count(*).

@ngn cliick

My life would be complete. ;-)

Do people code golf using SQL?

Cool. Thanks.

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.

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

@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.

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

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 I didn't notice that until now! Great. (Works on Safari, too.)

@Adám Hmm, since I'm living in an macOS-only environment right now I cannot compare...

@Adám Yes, it appears so.

Chrome on macOS.

APLcart's utility (to me) is phenomenal. Definitely deserves some stage time, if you ask me.

@Adam, yes, better now.

(Resizing the browser window does not fix it.)