Humour

Employment of wit and puns has a long history in the APL community. In particular, John Scholes was known for his wit. This article attempts to list and explain specific expressions of APL-themed humour.

Glyph puns

APL's unique glyphs are a constant source of puns and allusions. Most puns rely on the visual shape of the glyphs, or of various common or uncommon names for them.

• The song APL Blossom Time includes numerous references to primitives.

• A 2015 Dyalog blog post by Roger Hui, titled APL Puns collects many such glyph puns.

• Many APL glyphs have popular humorous names in addition to their official names. This includes splat for the Logarithm symbol (⍟), which is also often called Log (the common mathematical abbreviation for Logarithm) and an allusion to the symbol looking like a stylised tree log.

• Slash-functions may only be in our trains when accompanied by a calming constant or a responsible operator. This is a double entendre in that it sounds like by-law of a transit company while it actually speaks about forcing function/operator hybrids into acting as functions by either giving them a (constant) array left-argument or letting them be the operand of an operator.

• APLers often use individual glyphs as smileys, e.g. ⍨ or ⍥ or ⍤, or create custom emoticons like ○/ ("bye") or ¯\_(⍨)_/¯ ("shrug").

Rebuses

• Give-aways featuring the three glyphs ⍺*⎕ used to be common at APL conferences because these are the symbols traditionally produced when holding down the APL shifting key and typing APL.

• I was perched ⍤ the tower, giving my un÷d @tention 2 the ⌷ re∪ @ the ⌊ of the ⊂d ○ below me and ↑ing note of ¨ ⍨r's arrival time in my ⍟ ~ ⎕DL: I was perched atop the tower, giving my undivided attention to the squad reunion at the floor of the enclosed circle below me and taking note of each commuter's arrival time in my log without delay.

• ¨∊∪←=⊢2⍝∧?*: Each member of the union gets equal right to comment and question power.

• ⊢>+⌿÷≢: This monadic train indicates elements that are "greater than average" or "above average" and is used as catch phrase by Richard Park and Aaron Hsu.

The APLcart logo explained as a shopping cart.

Glyph art

As with ASCII art, APL glyphs are often used to draw pictures.

• Nativity scene:

      ⍟
  ⍒ ⍋⍛ ⍒⍒⍒⍤⍥

  Legend: ⍒ Joseph, ⍋ Mary, ⍛ Jesus, ⍒⍒⍒ three wise men, ⍤ donkey, ⍥ ox, ⍟ Star of Bethlehem.

• A Dyalog duck:

  ≤(∘)_
   (⍷_/

• The APLcart logo is a stylised profile view of a shopping cart in the form of the two glyphs Left-shoe Underbar and Upstile: ⊆⌈

APL vs J vs K

Comparison of dialects

There is a friendly rivalry between adherents of various APLs and derivatives which can lead to tongue-in-cheek attacks.

• APL vs J vs K is a collage of nine images that purport to illustrate how adherents of APL, J, and K, see the other languages. Going in ravel order, APLers think of APL as the ultimate tool of thought, J as APL's little brother that is too focused on mathematics, and K as being too restricted. J users see APL as the revered sage that has outlived itself using foreign (Chinese) characters that do not fit into a normal rectangle (thus being cut off on the right), J as the perfect all-round tool, and K as running after monetary gain (K being very fast, and often used for high-frequency trading). K users see APL as bloated and old, J as bloated and a joke full of .s and :s (as these two characters are used as suffixes to expand the number of ASCII symbols), and K as the key to winning the race.

Criticism of APL

Some features of APL are often ridiculed by APLers. Chief among them is the ability to set index origin, which leads to off-by-one errors even more often in APL than usually seen in programming.

Some APLers may enjoy playing a game of "complaint bingo" when conversing with the unreceptive.

• Roger Hui, a strong proponent of fixing index origin ― ⎕IO ― at zero is known for often inserting the phrase ⎕IO delenda est based on Cato's famous Latin oratorical phrase Carthago delenda est.

• In 2017, as an April Fools' Day joke, Dyalog Ltd. announced "a final improvement" to the "otherwise deprecated language feature", Branch, which would make it sensitive to the selected index origin. Such a change would cause a great many existing programs to break.

• Nick Nickolov has created an interactive form that claims to be an Array Language Implementation Permission Request addressed to the fictitious Ministry of Vector Processing and contains many in-jokes for APL language developers.

• This poem of unknown origin has been circulating the internet:

  'Tis the dream of each programmer,
  Before his life is done,
  To write three lines of APL,
  And make the damn things run.

Pop culture

References to Star Wars and Star Trek are common among programmers in general and APLers in particular.

• ⍣¯1 is a pathway to many abilities some consider to be unnatural. alludes to The dark side of the Force is a pathway to many abilities some consider to be unnatural. uttered by Darth Sidious in Star Wars: Episode III – Revenge of the Sith. The similarity was drawn because the Power operator (⍣), when given a negative number (e.g. ¯1) right operand, indicating the number of times to apply a function, works much like a black box. It will at times appear to solve "impossible" problems (by using numerical methods to what appears to be require symbolic manipulation) or give "fantastical" results by succeeding in reversing non-numeric operations. It can also choose any one of multiple correct answers, with no obvious system as to which answer is chosen. The full power of this operator is not documented.

Empty-array jokes

An array has an arbitrary number of elements. That number is a non-negative integer, which might be zero: for example, after removing items from a list or rows from a matrix.

Before array methods proliferated to scalar programming languages, many scalar programmers thought APL’s rigour with the handling of empty arrays somewhat absurd. APLers responded with a category of ‘empty array’ jokes. (Some are still listed at jsoftware.com.)

Nowadays most programming languages implement at least some array methods. A recent search for empty-array jokes failed to discover any.

Memes

Me at the APL Orchard

• The APL Orchard chat room is frequented by expert and neophyte APLers alike. A recurring theme is that newcomers feel inferior in the presence of those with more experience. In the anime illustration, the people listed are, from left to right, (Nick Nickolov (creator of ngn/apl and former employee at Dyalog Ltd.), dzaima (creator of dzaima/APL and 2020 2nd Place winner of the 2020 APL Problem Solving Competition), Adám Brudzewsky (lifelong APL programmer, founder of the APL Orchard, creator of Extended Dyalog APL, and employee at Dyalog Ltd.), and Woosuk Kwak (2020 Professional Prize winner in the APL Problem Solving Competition).

"Before and After" meme.

• Using APL can "spoil" a programmer, in the sense that they get frustrated by the lack of expressiveness in other programming languages. This is expressed by an instance of the "Before and After" meme.

• 15=∞ for sufficiently small values of ∞ or 99≈∞ for sufficiently small values of ∞ alludes to the use of e.g. ⍤0 15 or ⍤0 99 in APLs that have a limited maximum rank and do not support infinity as a numeric literal. In particular, Dyalog APL's maximum rank is 15, and so in the very specific context of the right operand of Rank, 15=∞.

• ngn's scans or ngn's cumulative reduces refers to Nick Nickolov's uncanny ability to come up with unusual uses of Scan for solving various problems, e.g. negating every other number with ⊢∘-\.

"Enjoying the flight" meme.

• Ryan "Rafvylf" Tosh created a meme featuring a plane taking off, but with a cat unknowingly in the wing or some part of the plane. The expert Jelly user and the APL/J/K user are enjoying the flight (learning Jelly or APL/J/K) while the cat (a non-array programmer) just barely hanging on.

Peak Engineering happened in the 1970s

• APL is a bit infamous in its character set of unusual glyphs, so Ace decided to make a "Peak Engineering" meme that turns that idea on its head.

BQN vs KamilaLisp

• Array programmers often disagree on the optimal set of primitives. While traditional array languages such as APL and BQN strive for completeness and minimalism, KamilaLisp implements every convenient functionality as a primitive.

Apples

Puns built upon how apple (/ah-pell/) and APL (/aye-pea-ell/) sound similar are often used both in visual media and in naming.

• An apple logo has been used by IBM in advertisements, badges, and stickers given out at APL conferences.

• Adrian Smith uses an apple icon on his APL-385 font site.

• Dyalog used an apple logo to celebrate 50 years of APL (part of Dyalog '16).

• APLTree ("apple tree") code library.

• Py'n'APL ("pineapple") Python-APL bridge (Python is often abbreviated "py-" when used in conjunction with other terms).

• SAWS and Acre APLSource as in "apple sauce".

• APL Orchard ("apple orchard").

• APLcart as in "upset the applecart" (spoil an established arrangement) as the project was intended to disrupt the traditional way of documenting APL.

• APL Seeds ("apple seeds") alluding to the conference aiming at those that are potentially growing into APLers, like apple seeds grow into apples (via apple trees). The event website features an apple grove.

• APL Campfire uses a promotional banner with an apple being roasted over a campfire.

• Tatin is a work-in-progress package manager, tarte Tatin being a specific type of apple pastry. Its logo is the logarithm symbol, coloured to resemble a stylised tarte Tatin.

• Cider is a project manager for Dyalog APL, cider being a fermented apple drink. Its logo is a stylised cup of apple cider.

• Dyalog APL by default uses the file name aplcore ("apple core") for its core dumps.

• The apljk subreddit is pronounced "applejack".

• 

  50 years of APL apple.

• 

  Community ad for the APL Orchard on Code Golf Stack Exchange.

• 

  An APL logo, proposed by Adám Brudzewsky.

• 

  The logo for APL seeds, a conference for new APLers.

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  BYTE featuring APL.