$ whois apl

APL

first released in 1966 · by Kenneth E. Iverson

$ guessprog --inspect apl

year: 1966
paradigm: array oriented
family: apl
memory: automatic gc
binding: dynamic
safety: strong

APL(7)

AUTHORS: Kenneth E. Iverson
HISTORY: Kenneth Iverson developed APL as a mathematical notation for describing algorithms while teaching at Harvard, and published it in his 1962 book "A Programming Language", which gave the language its name. After he moved to IBM, the notation was turned into a working implementation for the IBM System/360 in 1966. Programs are written with special symbols such as ⍴, ⍳ and ⌽, which originally required a dedicated typeball for IBM Selectric terminals. Iverson received the Turing Award in 1979 for this work.
USAGE: A niche language with a devoted community, still used in finance, insurance and actuarial work, mostly through Dyalog APL. Its array-oriented ideas strongly influenced J, K, Q and libraries such as NumPy.
SEE ALSO: APL on Wikipedia ↗

$ cat arrays.apl

⍝ Primes up to 50: remove every product of two numbers
N←50
(~R∊R∘.×R)/R←1↓⍳N

⍝ Average as a tacit train: sum divided by count
avg←+/÷≢
avg 3 1 4 1 5

⍝ Conway's Game of Life in one line
life←{↑1 ⍵∨.∧3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵}