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J can look like APL or English

 4 years ago
source link: https://www.tuicool.com/articles/iy2MNzZ
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APL, in contrast with J, uses unique, distinctive symbols with less overloading. The visual relationship between APL symbols and concepts is somewhat clearer than that of J.

Many J primitive functions map directly to APL primitive functions. It is therefore relatively easy to naively render J primitives as the corresponding APL symbol using extensions such as pretty-mode and/or prettify-symbols-mode in Emacs. For J primitives which don't have an APL equivalent, we have to get a bit more creative.

Here is an excerpt from my Emacs init file showing an example set of J to APL primitive mappings.

pretty-mode and j-mode need to be installed; prettify-symbols-mode comes with Emacs by default. 

(require 'pretty-mode)

(setq j-symbols
  '(("=\\."     . ?←)
    ("=:"       . ?⤆)
    ("_:"       . ?∞)
    ("<:"       . ?≤)
    (">:"       . ?≥)
    (">\\."     . ?⌈)
    ("<\\."     . ?⌊)
    ("\\*"      . ?×)
    ("%"        . ?÷)
    ("\\+\\."   . ?∨)
    ("-\\."     . ?¬)
    ("*\\."     . ?∧)
    ("%\\."     . ?⌹)
    ("\\+:"     . ?⍱)
    ("-:"       . ?≡)
    ("*:"       . ?⍲)
    ("%:"       . ?√)
    ("\\^\\."   . ?⍟)
    ("\\^:"     . ?⍣)
    ("\\$"      . ?⍴)
    ("\\$\\."   . ?ς)
    ("\\$:"     . ?∇)
    ("~"        . ?⍨)
    ("~\\."     . ?∪)
    ("~:"       . ?≠)
    ("|\\."     . ?⌽)
    ("|:"       . ?⍉)
    (",\\."     . ?⍪)
    (",:"       . ?⍿)
    (";:"       . ?⍧)
    ("#\\."     . ?⊥)
    ("#:"       . ?⊤)
    ("/\\."     . ?⍁)
    ("\\\\\\."  . ?⍂)
    ("/:"       . ?⍋)
    ("\\\\:"    . ?⍒)
    ("\\]"      . ?⊢)
    ("\\["      . ?⊣)
    ("\\[:"     . ?⍅)
    ("{\\."     . ?↑)
    ("}\\."     . ?↓)
    ("{:"       . ?⍏)
    ("}:"       . ?⍖)
    ("\""       . ?⍤)
    ("\"\\."    . ?⍎)
    ("\":"      . ?⍕)
    ("`"        . ?⍮)
    ("@"        . ?⍛)
    ("@\\."     . ?⌼)
    ("@:"       . ?⍜)
    ("\\&"      . ?∘)
    ("\\&\\."   . ?↺)
    ("\\&\\.>"  . ?¨)
    ("\\&:"     . ?⌾)
    ("\\?\\."   . ?⍰)
    ))

(defun prettify-j ()
  (progn
    (push '("a." . ?æ) prettify-symbols-alist)
    (push '("a:" . ?⍬) prettify-symbols-alist)
    (push '("A:" . ?⅍) prettify-symbols-alist)
    (push '("C." . ?ℂ) prettify-symbols-alist)
    (push '("d." . ?δ) prettify-symbols-alist)
    (push '("D." . ?Δ) prettify-symbols-alist)
    (push '("D:" . ?⌳) prettify-symbols-alist)
    (push '("e." . ?∊) prettify-symbols-alist)
    (push '("E." . ?⍷) prettify-symbols-alist)
    (push '("f." . ?ℱ) prettify-symbols-alist)
    (push '("i." . ?⍳) prettify-symbols-alist)
    (push '("i:" . ?ᵼ) prettify-symbols-alist)
    (push '("I." . ?⍸) prettify-symbols-alist)
    (push '("j." . ?ⅉ) prettify-symbols-alist)
    (push '("L." . ?ℒ) prettify-symbols-alist)
    (push '("NB." . ?⍝) prettify-symbols-alist)
    (push '("p." . ?ℙ) prettify-symbols-alist)
    (push '("p:" . ?⅌) prettify-symbols-alist)
    (push '("q:" . ?ℚ) prettify-symbols-alist)
    (push '("r." . ?∡) prettify-symbols-alist)
    (push '("y" . ?ω) prettify-symbols-alist)
    (push '("x" . ?α) prettify-symbols-alist)
    (push '("u" . ?⍶) prettify-symbols-alist)
    (push '("v" . ?⍹) prettify-symbols-alist)
    (prettify-symbols-mode)))

(pretty-add-keywords 'inferior-j-mode j-symbols)
(pretty-add-keywords 'j-mode j-symbols)

(add-hook 'inferior-j-mode-hook 'turn-on-pretty-mode)
(add-hook 'inferior-j-mode-hook 'turn-off-smartparens-mode)
(add-hook 'inferior-j-mode-hook 'prettify-j)
(add-hook 'j-mode-hook 'turn-on-pretty-mode)
(add-hook 'j-mode-hook 'turn-off-smartparens-mode)
(add-hook 'j-mode-hook 'prettify-j)

Here is a naive k-means clustering implementation in plain J:

init =. ([ ? #@:]) { ]
alloc =. {.@:I.@:(= <./)@:(+/@:*:@:-"1)
step =. (+/ % #)&>@:(alloc"1 2 </. [)
kmc =. ] step^:_ init

Here is how it looks like in Emacs with pretty-mode replacing many of the symbols:

vq6fUrm.png!web

The original J:

quicksort=: (($:@(<#[) , (=#[) , $:@(>#[)) ({~ ?@#)) ^: (1<#)

And J displayed with APL-like glyphs:

raAjMjq.png!web

This is probably equally unreadable if you are not already familiar with APL, but I do find it somewhat easier to read than the plain ASCII.


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