The APL Orchard

1:38 PM

@Hosch250 @EriktheOutgolfer @J.Sallé @Pavel @Cowsquack @wizzwizz4 @dzaima @H.PWiz @Uriel @Zacharý I have not scheduled any more lessons, and we've exhausted Dyalog OOP. Do you want me to continue the weekly lessons? If so, what subjects would interest you? E.g. coding styles or focus on tradfns/dfns/tacit, or…?

g o l f i n g l e s s o n s

Q: Tips for golfing in APL

I started one code golf challenge recently and it seems like the winner is GolfScript (surprise, surprise!). What's interesting is that there was another very strong competitor that had all chances to win over GolfScript. Its name is APL. I see a lot of answers written in APL here. It seems like ...

Tips are not actual lessons though

@EriktheOutgolfer I keep meaning to edit the OP there as it is so out of date, but I'm not sure what to write.

@J.Sallé but golfing is a recreational activity, and that means your creativity is involved in too, so I don't think there can be any lessons, everybody must figure on their own

the tips are a good starting point for that

1:44 PM

@EriktheOutgolfer Well, I for one still can't figure how to Dfn→tacit properly

@J.Sallé that's something your creativity is involved in very much, and, once you get a hang of tacit functions, it will be easy

I think I'll write an additional tips' post on using ⍨ cleverly: monadic +⍨ and ×⍨ and ⊥⍨. Are there others? (I should probably correct Marinus' post now that he's gone.)

@EriktheOutgolfer Well, you can certainly convert dfns to tacit in a mechanical fashion.

Yeah, I mean, there is a technique involved in it.

@Adám I think you should post a new answer if it's how to take advantage of them in a train

@EriktheOutgolfer It isn't. You'll see in a moment.

Hosch250

2:14 PM

I can't suggest anything without finishing the earlier lessons and writing at least some code.

2:45 PM

A: Tips for golfing in APL

Use ⍨ Avoid parentheses ⍨ (Commute) can save you bytes by avoiding parentheses. Whenever you have a function where the left argument needs to be parenthesised and the right argument does not, you can save a byte, e.g. (A<B)÷C → C÷⍨A<B. Double arrays To append a copy of an array to its end, us...

@Adám well, the ,\ in the "Reverse scan" example isn't exactly correct for a general-purpose reverse scan

@EriktheOutgolfer Yeah, I thought you might say that. Feel free to edit in a note with your clever alternative.

@Adám it's kind of different for \ and ⍀, and unfortunately no time now :(

@EriktheOutgolfer OK, later maybe. What I wrote does work for simple scalars.

      ]box on -style=max
      rss ← {⍺⍺⍨/∘⌽¨,\⍵}
      ,rss⊢3 3⍴⍳9
┌→────────────────────────┐
↓   ┌───────┐ ┌─────────┐ │
│ 1 │ ┌→──┐ │ │ ┌→────┐ │ │
│   │ │1 2│ │ │ │1 2 3│ │ │
│   │ └~──┘ │ │ └~────┘ │ │
│   └∊──────┘ └∊────────┘ │
│   ┌───────┐ ┌─────────┐ │
│ 4 │ ┌→──┐ │ │ ┌→────┐ │ │
│   │ │4 5│ │ │ │4 5 6│ │ │
│   │ └~──┘ │ │ └~────┘ │ │
│   └∊──────┘ └∊────────┘ │
│   ┌───────┐ ┌─────────┐ │
│ 7 │ ┌→──┐ │ │ ┌→────┐ │ │
│   │ │7 8│ │ │ │7 8 9│ │ │
│   │ └~──┘ │ │ └~────┘ │ │
│   └∊──────┘ └∊────────┘ │

@Adám looks like there are more serious problems than that to deal with (^)

3:00 PM

@EriktheOutgolfer Vectors of simple scalars.

(and now I realize that ⊢ was unneeded...ugh)

Zacharý

@Adám coding style. That was one MASSIVELY mass ping

3:17 PM

@Zacharý OO lessons' attendees + frequently in room

Zacharý

The amount of people tho...

Feeds

Adám has added an event to this room's schedule.

Adám has removed an event from this room's schedule.

Adám has added an event to this room's schedule.

@Zacharý Shows the popularity of the lessons and this room, I guess.

Zacharý

Yep, and spreading APL is always a good event. It should be do-APL in any scenario.

1 hour later…

Ven

4:29 PM

@Adám I'd like if you kept doing lessons, to be honest :-). Maybe a "best APL golfs this week", not sure at all.