The APL Orchard

Adám

00:32

@JeromeIbanes Welcome! Good to have you here.

Jerome Ibanes

01:18

Hello @Adám

glad to find people sharing my interests

Adám

:-D

I love your avatar. Good old days…

Jerome Ibanes

I seem to remember you said you were exposed to APL as a child?

oh yeah

Adám

Yes, my father was a professional APLer long before I was born, brought me to conferences from I was 1.

Jerome Ibanes

oh that's great

My grandfather showed me a terminal running xenix which had an apl session started, but I can't remember if it was running on a mainframe or xenix directly

must have been a 8086 or something like that

286 perhaps?

Adám

Funny. I don't know if my father was just never into UNIX-like systems, or if I just didn't experience it. He might have moved straight from typewriter+mainframe to a 5100.

Jerome Ibanes

01:24

but hey a few kilobytes of workspace is plenty

it would be interesting to recreate the typewriter experience with a dot-matrix printer or sometihng along those lines

not sure how they'd deal with the glyphs, I suspect there are ways.

Adám

Dot matrices are nothing like Selectrics…

Jerome Ibanes

didn't apl11 ship with epson printer support anyway?

Adám

Everything did, no?

Jerome Ibanes

right, I'm not saying we should go the whole way to a selectric

oh probably, I haven't used a printer in some time

were people commonly sharing a workspace on mainframe apls?

Adám

What do you mean by sharing?

Jerome Ibanes

01:28

more than one operator attached to the same workspace

Adám

Nah, each user had their workspace, but could copy from the utility workspaces.

Jerome Ibanes

I see

Adám

If I had the time and money (?) I'd want to create a miniature IBM/360 closet containing a Raspberry Pi running this.

Jerome Ibanes

oh yeah

I suppose you've tried mvt4apl?

Adám

I have, and yes, or that.

Jerome Ibanes

01:31

oh actually mvt4apl might even be using your fonts

I wouldn't be surprised

Adám

It uses the APL2741, I think.

Jerome Ibanes

I see

which font do you commonly use?

Adám

I change sometimes depending on mood. APL385, APL386, SAX2, DejaVu Sans Mono.

Jerome Ibanes

yeah I really like APL386

Adám

Unfortunately, it has hinting issues that I don't know how to fix.

Jerome Ibanes

01:35

how did you make them?

Adám

APL385 just took APL385 and edited in FontForge. SAX2, I extracted from a PDF, then reordered and edited in FontForge.

Jerome Ibanes

that's a lot of work

SAX had very interesting features and expandability options

although I've only used it on linux

Adám

@JeromeIbanes Do you have it available? I remember it was freely downloadable from Soliton, but I only downloaded the manual at the time. The day I had Linux available, Soliton was gone.

Jerome Ibanes

most certainly

I probably have the latest version too

should I email it to your personal address?

Adám

I suppose it is truly abandonware. Nobody seems to have inherited any rights at all.

@JeromeIbanes Yes, please.

Jerome Ibanes

01:40

I believe you are right

one moment

Adám

No rush. I need to sleep soon anyway… approaching 2 AM.

Jerome Ibanes

you should have it

I have more stuff for sax, we can chat later

Adám

@JeromeIbanes ACK.

Jerome Ibanes

cool

have a good evening

or morning

Adám

⍨

Fmbalbuena

01:53

@Adám can you post a quiz for me?

Adám

@Fmbalbuena This is a hard one: Given a number, round it to the closest integer, with 5 rounding up. E.g. 1.3 → 1, ¯4.7 → ¯5, 6.5 → 7, ¯0.5 → 0

Fmbalbuena

@Adám not a quiz but challenge.

Adám

@Fmbalbuena I'm not sure what the difference is. Do you think you can write a function that can do this?

Fmbalbuena

@Adám quiz example: what does this dfns do? another example: What is the obscured symbol in the following dfns?

Adám

Ah, ok.

Hard: What does this function do? {0 0≡2⍴0⍴⍵}

Try it with arguments like 'hello' and 'a' and 1 2 3 and 42

Fmbalbuena

02:03

@Adám checks if there is a integer in a list or the "⍵" is a integer?

Adám

Very close. It checks if the argument is numeric.

Fmbalbuena

@Adám but why?

Adám

Remember a while ago you asked me for the empty list in APL?

Fmbalbuena

yes

Adám

I told you that there's a difference between an empty bag of potatoes and an empty shopping list.

Fmbalbuena

02:06

@Adám what does this mean?

oh

understood why.

Adám

So now you understand how this function works too?

Fmbalbuena

yes

another quiz but What is the obscured symbol in the following dfns? (use "⋄" for obscured symbol)

Adám

Great. You're really getting the hang of this.

OK, what is the obscured symbol (∎) in the dfn {∎≢⍵} which is supposed to enumerate the elements of its argument?

Fmbalbuena

idk. a hint?

Adám

If you give the function 'ABC' it should give 1 2 3.

Fmbalbuena

02:12

but uses "≢" which made me harder

Adám

Ah, I'm so sorry. I forgot you didn't learn monadic ≢ yet.

What is ∎ in the dfn {∎⍴⍵} so it enumerates the elements of its argument?

Fmbalbuena

i learned "≢" which is opposite of "≡".

Adám

Yes, sorry.

Fmbalbuena

a hint?

Adám

The function is supposed to give a list with as many elements as its argument has elements (numbers or characters), with 1 for the first element, 2 for the second, etc.

10 10 10 10 → 1 2 3 4

Fmbalbuena

02:18

reveal?

Adám

'Hello' → 1 2 3 4 5

@Fmbalbuena No, you can figure this out. How about you forget the quiz, and simply try to write this function from scratch?

Fmbalbuena

scratch?

Adám

It means to write a new function, not using any existing code.

In other words: Write a function that takes an argument list, and returns a list that has as many elements, but they are 1 2 3…

Fmbalbuena

monad ⍴ means length of elements?

Adám

Yes. Ah, we never covered that either, did we?

I'm probably too tired. It is almost 02:30 AM here.

Fmbalbuena

02:23

@Adám 02:22

in your timezone

Adám

Yes, and for the bot: ⎕←⎕TS

Oh, bot is down.

Fmbalbuena

Are you down? ⎕←'No, i'm not down'

TryAPL

@Fmbalbuena Yes I am

Fmbalbuena

Why bot is down?

Adám

Probably because it needs Stack Exchange APIs and all of Stack Exchange interactivity is down.

Fmbalbuena

02:28

which Stack Exchange APIs?

Adám

I suppose.

hyper-neutrino

specifically the bot is failing to log in

Fmbalbuena

ok

hyper-neutrino

@TryAPL ok it took me a second to remember who owns this account and i was rather concerned for a sec :p

Adám

;-)

Razetime

03:08

@Adám ah i should fix that

M4X_

07:09

Hi guys. Quick question. suppose i have a list ..... 'a', 'b', 'c'.

How do I drop 'a' from the list such that the result is 'b', 'c'.

What would be the most effective J verb that does this ?

hyper-neutrino

07:39

⎕←'hello'

TryAPL

@hyper-neutrino hello

hyper-neutrino

alright, bot is working again, apologies for the delay, I forgot to turn it back on

Adám

08:18

@M4X_ Behead: }.

Adám

09:12

Riddle: 0J1.133

Adám

09:30

@FawnLocke Instead of all the inline td styles, you can have a single td:first-child {text-align: right} rule.

Bubbler

@Adám What is this? Are we supposed to find a "simple" expression that gives the value?

Adám

@Bubbler Yes, that approximate value, and the expression, when read aloud, will be a timely phrase.

A more precise value is 0J1.1330900354567985.

Bubbler

VTC as too broad :P

Adám

09:45

It is a riddle/joke, not a CMC.

Fmbalbuena

@Fmbalbuena i forgot to break the quote

@Adám "⍳"

Adám

Very good.

Fmbalbuena

but i forgot the "⍳" symbol

Adám

Then it was a good quiz – to remind you.

Want another test?

Fmbalbuena

yes

Adám

09:53

Explain the difference between a↑b and a⍴b

Fmbalbuena

@Adám 6↑'a' will return 'a ' but 6⍴'a' will return 'aaaaaa'.

uh

whitespace not working

6↑'a' will return

a
^

still not working

but it gives a and 5 spaces

Adám

Right. Good.

Btw, if you but backticks, it works: a (this is `a `)

Fmbalbuena

(this is a )

Adám

And of course, backticks with quotes works too: 'a ' (this is `'a '`)

Fmbalbuena

but why the previous not working

xpqz

09:58

@Adám have you even been to bed yet??

Adám

Yes, why?

xpqz

You keep long hours...

2am, and still here at 10am?

Adám

I've been up for a couple of hours :-)

xpqz

Your coffee must be first-rate.

Fmbalbuena

How to teach APL in 4 easy steps:

1- teach

2- sleep in 2 AM

3- wake up in 6 AM

4- repeat

xpqz

10:00

@RGS on the CSS thing, ok if I email you, as probably a bit ECHAN for here...?

Adám

@xpqz My caffeine intake probably averages about 100 mg per month, distributed as a single 200 mg dose every couple of months.

@xpqz Yes, you can. He does it for work!

xpqz

Hahha :)

Adám

Well, I occasionally eat a little chocolate. I guess it has a tiny bit of caffeine.

xpqz

Coffee is my biggest vice. Working from home has quaadrupled my intake due to proximity of the coffee maker.

Adám

It helps that coffee is one of the otherwise very few things I don't like the taste of. So I swallow a bitter pill only when absolutely necessary.

RGS

10:21

@xpqz You can email me, 100%, I just don't know what ECHAN means :P

xpqz

In this case "the inappropriate channel", from an error you occasionally see in c/c++

PyGamer0

11:07

CMC: Given a vector of length 3 (call it a), compute all roots of the quadratic a1x²+a2x+a3(=0)

aplcart not allowed

Adám

Maybe I should have called APLcart "AskAdam"…

PyGamer0

@Adám how to convert this to tacit: {∘.=⍨⍳⍵}?

Adám

@PyGamer0 ∘.=⍨⍳

PyGamer0

oh

@Adám "AskingAdám"?

Fawn Locke

11:27

@Adám That'll only work for the first item in each row. If CSS had a "child before element" selector it'd be none-ugly. I will write APL to generate this page after I'm done - which I'll get onto in a few hours :)

rak1507

@PyGamer0 shortest I've got is 34, wbu

Adám

@FawnLocke My bad. Anything wrong with using :nth-child(4n+1)?

Fawn Locke

Yeah, that'd probably work.

Adám

Just exempt the syntax table.

M4X_

11:56

@Adám thanks!

rak1507

@Adám any hint?

Adám

@rak1507 What's in the news?

rak1507

omicron?

or that christmas party?

Adám

Tech news.

rak1507

oh log4j lol

Adám

12:00

⋄ j←0J1 ⋄ 4⍟j

TryAPL

@Adám 0J1.133090035

Adám

12:33

Not sure why I think this is pretty cool: ⎕←m←1=?4 4⍴3 ⋄ '' ⋄ ⍸@⊢m

TryAPL

Adám

But I'm definitely putting it on APLcart.

Fawn Locke