The APL Orchard - 2019-06-14

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4:46 AM

@TessellatingHeckler See here: That will do for the nonce, but we'll need a better answer for the long term.

5:00 AM

@dzaima Yeah, it is awkward due to frames, but you can link to APLcart with ?q=nonce

Btw, if APLcart should get a dedicated domain, what should the TLD be? aplcart.it? aplcart.info? aplcart.fyi?

1 hour later…

6:25 AM

@Adám still interested in contest feedback?

@ngn Of course, but you can email it to contest2019@dyalog.com too/instead.

@Adám the pdf changed without notification :|

@ngn Really? For all but trivial changes, you should have gotten an email if you're signed up.

@Adám maybe it was considered a trivial change

i'm looking at the 2 pdfs side by side now, i can see some things were fixed but not all

Jun 10 at 19:23, by ngn

"Black to move" is totally wrong - there is no file i on a chessboard (is that f?) and some of the rook's moves seem vertically reversed

^ i did mean "totally", not just s/i/f/

@Adám you're a chess player. look at the position for "black to move". can the black rook go to c2 at all? let alone capture something and give a check

@ngn I wasn't involved in the formulation of phase II problems :-(

6:37 AM

@Adám ok, i'll send a raven to contest2019@

@ngn Thanks! Can we maybe hire you for proofreading/sanity check next year?

@Adám maybe. a year is a long time. as long as i'm not busy then, i'd be open to it

@ngn as i was writing the email, i realised what's going on :) that must be Rxe2+ inst of Rxc2+. it was probably ocr-ed or transcribed by hand. that explains the i-s instead of f-s too.

1 hour later…

8:10 AM

lesson learned from "permutation order": don't trust the title, read the problem and understand the examples before you start coding :)

@Adám aplc.art?

@ngn Yeah, I noticed that one, but I think that level of URL hacking is dumb — and this one is expensive too.

6 hours later…

1:49 PM

@Adám If I have a long string, how can I separate it into a vector of 2-element vectors? E.g. 'ABCDEF' → AB CD EF

⎕←(⊢⊂⍨1 0⍴⍨≢)'ABCDEF'

@Adám
┌──┬──┬──┐
│AB│CD│EF│
└──┴──┴──┘

⎕←(⊢⍴⍨2,⍨.5×≢)'ABCDEF'

@Adám
AB
CD
EF

I knew I had to use ⍴ somehow, I just didn't figure it out.

@Adám thanks!

1:52 PM

@J.Sallé In Extended ¯1 2⍴'ABCDEF' and in dzaima ⍬2⍴'ABCDEF'

@J.Sallé Actually:

⎕←((≠\=⍨)⊂⊢)'ABCDEF'

@Adám
┌──┬──┬──┐
│AB│CD│EF│
└──┴──┴──┘

obligatory speed-test - obviously a matrix is 100x faster, but other than that there's not much variance

Hm, I think I'm doing something wrong. ((≠\=⍨)⊂⊢),/⍕¨6×⍳325 throws a domain error, but the part following the ,/ is a string, isn't it?

I'm very rusty, as you can probably tell

@J.Sallé you need ⊃,/

@J.Sallé Just use ∊ instead of ,/

2:00 PM

Oh duh.

Totally forgot that ∊ would work there

@Adám ¯1 2⍴∊⍕¨6×⍳325 throws a Domain error in Extended

@J.Sallé There's also the not-just-for-GoL stencil:

⎕←⊢∘⊂⌺(⍪2 2)⊢'ABCDEF'

@Adám
┌──┬──┬──┐
│AB│CD│EF│
└──┴──┴──┘

@J.Sallé your list has an odd number of elements

Huh, I'd thought it'd pad it somehow. I'll stick to dyalog anyways

Thanks guys :D

@J.Sallé use ¯1 for strict, ¯.5 for chop, ¯1.5 for recycle.

Padding is not in the nature of ⍴ (except for when reshaping empty arrays).

@dzaima Btw, APLcart now makes it easy to "perma"link: just copy the current URL.

3 hours later…

5:10 PM

@Adám is there a way to make this 1∘{⍺⌷n←⍵,1+2|⍺⋄(1+⍺)∇⍵,n}1 2 2 not exit after ⍺⌷? Using pick results in the same

@J.Sallé why are you even doing ⍺⌷ if you're just gonna ignore it?

or do you mean that as to store that as the return value, run the next line & return the saved value?

@dzaima I intend to print an infinite run of a sequence, so I'm storing the index to be returned in ⍺, since the seed I begin with (in ⍵) already has 3 elements

@J.Sallé which part is supposed to do the printing then if the function's gonna recurse infinitely?

adding a quad seems to give a sequence and fixes the problem

the general solution is to add a _← or join the statements with ⊢ or ⊣ depending on the situation

@dzaima I sent the wrong function actually, it's missing a ⎕← after the ∇

@dzaima it's not the right sequence though, it's close but not the same

@J.Sallé so {⍺⌷n←⍵,1+2|⍺⋄(1+⍺)∇⎕←⍵,n}? Still, ⍺⌷ does and should do exactly nothing never except error if the index is invalid

5:23 PM

Okay, I still need to think it through then

what do you want the ⍺⌷ to do?

Print the ⍺th element of ⍵

and why is ⎕←⍺⌷... not exactly what you want then?

@dzaima I think that'll work, I might just be generating the sequence wrong

6:12 PM

Okay, I've ironed out the issues and got this monstrosity: 2∘{⎕←(⍺-1)⌷⍵⋄n∇⍵,∊⍵[n←1+⍺]⍴1+2|⍺}1 2 2

It does what I want, but I don't think that's a submittable function

@J.Sallé is a full program allowed? it works as one

you can also get rid of the ∘

@dzaima Ah yes. Leftover artifact.

OP says I may write a Program or function, so I guess it is valid

-2 bytes by starting with a 1 lower ⍺

@dzaima Nice, thanks!

also why the ∊?

6:32 PM

@dzaima that's another leftover actually.

6:56 PM

@J.Sallé I don't think ⍵[2+⍺] is the last element of ⍵ in the explanation

Ah yeah. I'll fix it

another random speedtest with unexpected results

7:18 PM

oh, seems that the last test case ruined the reliability of the first two, which are actually pretty equal

yep

How the heck does one interfere with the other two

@J.Sallé I'd guess it's related to how multiple executions are packed together or maybe even how cache is used (i.e. the last one ruins everything, making the first have to reload everything, but that's just a guess)

aka benchmarking is hard

Indeed.

I blame Java

@J.Sallé ಠ___ಠ

hey i still have a lot of unused keys on my second keyboard, i could use a couple to insert ಠ_ಠ, ¯\_(ツ)_/¯ etc., 3 keystrokes for those is just way too much

7:36 PM

@dzaima That's the first lesson I learned in my first OOP class. "When in doubt, blame Java."

I approve of the ascii art with a single keystroke

I have ¯\_(ツ)_/¯ in my phone's keyboard shortcuts because it's just too good not to have

@J.Sallé yeah i still don't have an easy way to write those on phone, it's been annoying a couple times :/

Look into keyboard shortcuts. I use an iPhone and it's pretty easy to configure, so I assume it's even easier in android phones

why does xdotool type hang the whole desktop for a second when anything's typed ಠ_ಠ

oh

8:01 PM

Lol that issue has been open since 2012

I can't even joke that it'll be fixed when our theme releases anymore :c

1 hour later…

TessellatingHeckler

9:21 PM

@J.Sallé This is the first problem on the Dyalog contest Phase1, "Chunky Monkey", btw. And something I've found both desirable and annoying to do in Python and PowerShell several times over the years, neat in APL.

speaking of typos in the Dyalog competition, Phase 1, 4 has the text "For those not familiar with the game a chess"

@TessellatingHeckler That's just the Crockney accent geting the better of whoever wrote it

@TessellatingHeckler I actually solved that problem, but didn't remember it was it until you mentioned it

TessellatingHeckler

@J.Sallé I solved it, but obviously not as neatly as Adam did here :P

I can't see the difference between "nest" and "box"

What do you mean by 'box'?

AFAIK boxing is a system function

TessellatingHeckler

I mean left-shoe, enclose

vs left-shoe-underline, nest

⎕←⊂1 2 3

@TessellatingHeckler
┌─────┐
│1 2 3│
└─────┘

TessellatingHeckler

9:33 PM

⎕←⊆1 2 3

Oh, I see.

@TessellatingHeckler ⊆ only encloses depth one things, i.e. ⊆(1 2 3)(4 5 6) just returns it's arguments

They work the same with scalar vectors

imo it's an awful function though, if it's needed you've done something very wrong already

TessellatingHeckler

@dzaima Dyalog's competition suggests it for Phase 1 problem 5

although I don't yet see how to use it in an answer

9:35 PM

@TessellatingHeckler quote from the description of phase I: This is largely pedantic

TessellatingHeckler

but then I don't see how to use "membership" to answer question 6 either, it seems easy without it

@TessellatingHeckler You can see the difference if you do something like this:

⋄←⊂1 2 (3 4)⋄⊆1 2(3 4)

@J.Sallé
SYNTAX ERROR

TessellatingHeckler

@dzaima oh was I supposed to read the description :D

I forgot how to multiline apparently

⎕←⊂1 2 (3 4)⋄⊆1 2(3 4)

9:37 PM

@J.Sallé
┌─────────┐
│┌─┬─┬───┐│
││1│2│3 4││
│└─┴─┴───┘│
└─────────┘

@TessellatingHeckler not really, I'm just saying that the need for requiring the usage of ⊆ is pointlessly set by the challenge itself

⍞←⊂1 2 (3 4)⋄⊆1 2(3 4) ⍝ maybe this?

@J.Sallé

@J.Sallé if a line starts with ⋄ or ⎕← it's executed exactly as-is, so ⎕←...⋄⎕←...

Nope

TessellatingHeckler

9:38 PM

@dzaima ohh in the context of the problem it's to distinguish one string from several strings

⎕←⊂1 2 (3 4)⋄⎕←⊆1 2(3 4) ⍝ okay now it's gonna work

@J.Sallé ⋄⊆1 2(3 4) by itself doesn't print anything (this is not the REPL)

@J.Sallé and the bot hates comments with a passion

Goddamnit I give up

⎕←⊂1 2 (3 4)⋄⎕←⊆1 2(3 4) ⊣ 'there you go (hopefully)'

@dzaima
┌─────────┐
│┌─┬─┬───┐│
││1│2│3 4││
│└─┴─┴───┘│
└─────────┘
┌─┬─┬───┐
│1│2│3 4│
└─┴─┴───┘

9:39 PM

Yeah that.

⎕←⊆'hello' ⋄ ⎕←⊆'hello' 'world' ⊣ 'imo a better example'

@dzaima
┌─────┐
│hello│
└─────┘
┌─────┬─────┐
│hello│world│
└─────┴─────┘

I've been meaning to refactor some of this bot's code to work in the k room also

If I have the time I might fix its behaviour regarding comments as well

TessellatingHeckler

i get kinda get it now; ⊆ will box a single vector, but won't box an array of multiple vectors

@J.Sallé Adám said something about the behavior being as it is so errors work well, but removing them before execution would work

TessellatingHeckler

9:42 PM

did this room change from yellow-theme to green-theme to be more Apple-ish or more Matrix-hacker-ish?

78

Q: Congratulations! Your site design is now live!

You may have noticed that the site got a bit less blue today! Thank you so much for your input over the last few weeks. This has been a great process and I really hope you like your new theme. We took your very helpful feedback and made some adjustments Reworked the logo to look more like a ...

discussion featured design announcement

that applies to codegolf.SEs chatrooms too

TessellatingHeckler

ah, ok

@dzaima Yeah, I intended to just strip everything from ⍝ onwards before sending the code to execute

TessellatingHeckler

/quickly puts ⍝ in a char vector

That wouldn't matter because I think the bot parses them as strings

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