vendethiel / trying.apl

APL is the greatest language ever

Trying APL

This repository contains a handful of basic APL snippets, demonstrating each and every operator's purpose and behavior. The ex/ directory contains a few examples, mostly from Programming Puzzles & Code Golf Stack Exchange.

Table of contents

Evolution level: 1

Filename	Symbol name	Symbol	Monadic	Dyadic	Operator (higher-order)
assign	left arrow	←		Assignment
index	iota	⍳	Index Generator	Index of
reduce-replicate	slash	/		Replicate	Reduce
shaped	rho	⍴	Shape-of	Reshape
mix-take	up arrow	↑	Mix	Take
enclose	left shoe	⊂	Enclose	Partitioned enclose
first-pick	right shoe	⊃	First	Pick
rand	question mark	?	Roll	Deal
commute	tilde dieresis	⍨			Commute
element-s	epsilon	∊	Enlist (flat)	Membership
rev-rot	circle stile	⌽	Reverse (inner)	Rotate (inner)
rev-rot-first	circle bar	⊖	Reverse first (outer)	Rotate first (outer)
not-without	tilde	~	Not	Without
cat	comma	,	Ravel	Concatenate
logic	Logical {N,}{and,or}	∧, ∨, ⍲, ⍱		and, or, nand, nor
compare	{Not,} Equal | {Greater,Lower} than{,or equal}	<, >, ≤, ≥, =, ≠		lower, greater, lower-or-eq, greater-or-eq, eq, not-eq
grade	grade {up,down}	⍋ (up), ⍒ (down)	Grade {Up,Down}	Dyadic Grade {Up,Down}
each	dieresis	¨			Each
function	braces	{ and }	⍵ (monadic argument) / ⍵⍵ (function monadic argument)	⍺ (dyadic argument) / ⍺⍺ (function dyadic argument)	Function
depth-match	equal underbash	≡	Depth	Match
tally-notmatch	equal underbash slash	≢	Tally	Not-match
statement	diamond	⋄		Statement separator
short-circuit	colon	:		returns ⍵ from ∇ if ⍺=1
compose	jot	∘			Monadic compose (e.g.: ⍴∘⍴) / Currying
pointfree (implicit composition)
inner-product	dot	.			Inner product (e.g.: +.×)
outer-product	jot + dot	∘.			Outer product (e.g.: ∘.+)
rank	jot diaerisis	⍤	(⍵ is the new rank of the operator)	changes the rank of ⍺⍺
variant	quad colon	⍠	Sets option value
key	quad equal	⌸	Returns an scalar vector (key, positions for the key)

trying.apl's Issues

show more assignment

a+<-3

remove non-alphanumeric characters for palindrome

• use element-of to find which elements are part of the string, then use / to filter (as in 0 1/'ab').
• the filtering itself (take only elements that are in a and b) could probably be another example, though ;-).
• And that use of / probably needs to be documented
• demonstrate ~ as 'remove from'

add ⍠⌸⍣⌹

especially ⍣ used with ⌸ to create fix (which should be its own example!)

• ⍠
• ⌸
• ⍣
• ⌹

change "mix-take" (and others) mentions

because the filename changed

add the examples directory

Add intro?

The tables are completely unreadable on mobile. Do you think you can throw a one paragraph description on the top of the readme to encourage people to link the repo?

make sure "↓" is correctly documented as "envectoring"

more compose

Compose: (f g) Y
Compose: (A g) Y
Compose: (f B) Y
Compose: X (f g) Y

Remove "maybe" and "ʔ" from the repository description

Add inner product example

add a negative example to take & drop

Add variations of assignment

Namely, (A B C)<larrow>1 2 3 and (A B C)<larrow>1

add ⌿\⍀

• ⌿
• \
• ⍀

figure out why tryapl.org's "⌸" doesn't work in gnu apl

then use & explain it

more indexing/subindexing

http://aplwiki.com/LearnMoreApl/SelectiveSpecification

document numbered reduce

in reduce-replicate.apl

explain the symbols used in the examples

document ex/all-numbers

show ":" for return

fix "arguments"'s table entry

function (alpha and omega are the arguments)

Sometimes the file "mix-take" is referred to as "mix-pick"

fix runner

Add αα/ww

and add a reference to it in commute

add rank operator