Extended Dyalog APL

Extended Dyalog APL
Developer	Adám Brudzewsky
Released	2018
Latest release	unversioned/2021-06-07
Array model	nested
Index origin	0 or 1
Function styles	tradfn, dfn, tacit
Numeric types	complex floats, decimal floats
Unicode support	full
Implementation language	Dyalog APL
Source code	GitHub
Platforms	Dyalog APL
License	MIT
Documentation	README
Run online	TIO
Influenced by	J
Influenced	Dyalog APL, dzaima/APL, BQN, Dyalog APL Vision

Extended Dyalog APL features extended domains of existing primitives and quad names and adds a few new ones to Dyalog APL. It was an experimental project that is no longer maintained. Quoting from project README.md:

This project serves as a breeding ground for ideas. While some have been adopted into Dyalog APL proper, it is unlikely that many will be. Furthermore, Dyalog 18.0 gave a different meaning to monadic ≠ than proposed here, leaving Extended Dyalog APL as a deadend.

The role of Extended Dyalog APL as breeding ground for ideas was followed Dyalog APL Vision, also by Adám Brudzewsky.

Influence

Many of the extensions have been adopted into dzaima/APL, while Dyalog APL added Constant (⍨) and introduced non-experimental case conversion as a ⎕C function rather than the proposed operator. Dyalog is also planning to add Reverse Compose, From, and Depth.

Features

The following extensions were made:

Name	Glyph	Type*	Extension
Back Slash	\	🔶	∘.fwhen dyadic, allows short and/or multiple left args
Back Slash Bar	⍀	🔶	⊢∘fwhen dyadic, allows short and/or multiple left args
Bullet	∙	🔺	Inner product and Alternant
Circle Diaeresis	⍥	🔺	Over and Depth
Circle Jot	⌾	🔺	Complex/Imaginary
Del Diaeresis	⍢	🔺	Under (a.k.a. Dual)
Del Tilde	⍫	🔺	Obverse;⍺⍺but with inverse⍵⍵
Diaeresis	¨	🔵	allows constant operand
Divide	÷	🔵	monadic converts letters to title case when possible
Dollar Sign	$	🔺	string enhancement ${1}:1⊃⍺, ${expr}:⍎expr,\n:JSON
Down Arrow	↓	🔵	allows long⍺
Down Shoe	∪	🔵	allows rank>1
Downstile	⌊	🔵	monadic lowercases letters
Down Tack	⊤	🔶	2s as default left argument
Ellipsis	…	🔺	fill sequence gaps (dfns workspace'sto⍤1
Epsilon Underbar	⍷	🔶	monadic is Type∊with⎕ML←0
Equals	=	🔶	with TAO; monad: is-type
Greater Than	>	🔶	with TAO; monad: is-strictly-negative/is-visible
Greater Than Or Equal To	≥	🔶	with TAO; monad: is non-positive/is-not-control-character
house	⌂	🔺	prefix for contents of dfns workspace
infinity	∞	🔺	largest integer (for use with⍤and⍣)
Iota	⍳	🔵	Unicode version of dfns workspace's iotag
Iota Underbar	⍸	🔵	allows duplicates/non-Booleans
Iota Underbar Inverse	⍸⍣¯1	🔵	givenr, findsnso thatr≡⍸n
Jot Diaeresis	⍤	🔵	allows constant left operand, Atop with function right operand
Jot Underbar	⍛	🔺	reverse compositionX f⍛g Yis(f X) g Y
Left Shoe	⊂	🔵	allows partitioning along multiple trailing axes, with short ⍺s, and inserting/appending empty partitions
Left Shoe Stile	⍧	🔺	monad: nub-sieve; dyad: count-in
Left Shoe With Axis	⊂[k]	🔵	as⊂, but called with left operand
Less Than	<	🔶	with TAO; monad: is-strictly-positive/is-control-character
Less Than Or Equal To	≤	🔶	with TAO ; monad: is-non-negative/is-invisible
Minus	-	🔵	monadic flips letter case
macron	¯	🔵	as prefix to name or primitive means its inverse
negative Infinity	¯∞	🔺	smallest integer (for use with⍣)
Nand	⍲	🔶	monad: not all equal to type
Nor	⍱	🔶	monad: not any equal to type
Not Equal To	≠	🔶	with TAO; monad: is-non-type
Percent	%	🔺	f%andA%: probability-logical function (mapping arrays)
Quad Diamond	⌺	🔶	auto-extended⍵⍵, allows small⍵, optional edge spec(s) (0:Zero; 1:Repl; 2:Rev; 3:Mirror; 4:Wrap; -:Twist) with masks as operand's⍺
Question Mark	?	🔵	⍺?¯⍵as norm dist stddev ⍵and optional mean⍺←0
Rho	⍴	🔵	allows omitting one dimension length with¯1
Right Shoe Underbar	⊇	🔺	monadic discloses if scalar, dyadic indexes sanely
Right Shoe Underbar With Axis	⊇[k]	🔺	as above, but called with left operand
Root	√	🔺	(Square) Root
Semicolon Underbar	⍮	🔺	(Half) Pair; use↑⍤⍮to add axis
Slash	/	🔵	allows short and/or multiple left args
Slash Bar	⌿	🔵	allows short and/or multiple left args
Star Diaeresis	⍣	🔵	allows non-scalar right operand incl.∞and¯∞and array left operand
Stile	|	🔵	monadic normalises letters to lowercase (upper then lower)
Stile Tilde	⍭	🔺	monadic is factors; dyadic depends on⍺: 0=non-prime?, 1=prime?, ¯1=primes less than⍵, ¯2=⍵th prime, 4=next prime, ¯4=prev prime
Tilde	~	🔵	monadic allows probabilities, dyadic allows rank>1
Tilde Diaeresis	⍨	🔵	allows constant operand
Times	×	🔵	set/query letter case (lower:¯1, title:0, upper:1)
Up Arrow	↑	🔵	allows long⍺
Up Shoe	∩	🔶	monadic is self-classify; dyadic allows rank>1
Upstile	⌈	🔵	monadic uppercases letters
Up Tack	⊥	🔶	2 as default left argument
Vel	∨	🔶	monadic is Descending Sort
Wedge	∧	🔶	monadic is Ascending Sort
Case Convert	⎕C	🔺	fn ⎕Capplies case-insensitively,array ⎕Ccase-folds
Error Message	⎕EM	🔺	Self-inverse⎕EM
Namespace	⎕NS	🔵	allows⎕NS names values(tries to resolve⎕ORs)
Namespace inverse	⎕NS⍣¯1	🔺	allows(names values)←⎕NS⍣¯1⊢ns(returns⎕ORs for ns/fns)
Unicode Convert	⎕UCS	🔵	scalar when monadic

* 🔺 means new feature 🔶 means added valence 🔵 means expanded domain