View source for Typing glyphs

APL uses a range of [[glyphs|special graphic symbols]] to represent most functions and operators. While keyboard mappings become [[mnemonics|memorized]] over time, entering APL characters can frustrate the [[learning resources|beginner]]. However, a study involving high school students found that typing and using APL characters did not hinder the students in any measurable way. There are several convenient ways to enter the glyphs.
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[[File:Dyalog US keyboard.jpg|thumb|right|US keyboard with [[Dyalog APL]] glyphs]]
== Hardware ==

Once the keyboard map is configured to one's liking, it may be beneficial (especially for new users learning APL) to have a keyboard with APL symbols. There are a few solutions to this, such as purchasing a dedicated desktop keyboard, key caps for mechanical keyboards, or a keyboard decal.

{| class=wikitable
! Item !! Type !! Layout !! Languages !! Seller
|-
! rowspan=2 | Keyboard
| [[wikipedia:Model_M_keyboard|Model M]] || [[Dyalog APL|Dyalog]] || 🇺🇸 || [https://www.amazon.com/Unicomp-Classic-Buckling-Spring-Keyboard/dp/B01M7V3M61/ref=sr_1_8 Amazon].
|-
| [[wikipedia:Cherry (company)|Cherry]] || Dyalog || 🇺🇸 🇬🇧 🇩🇪 🇩🇰 || [https://www.dyalog.com/apl-font-keyboard.htm#mainContent Dyalog]
|-
! rowspan=4 | Key caps
| Model M || Dyalog || 🇺🇸 ||[https://www.pckeyboard.com/page/product/USAPLSET Unicomp]
|-
| CannonKeys || [[APL2]] || 🇺🇸 || [https://cannonkeys.com/products/cannoncaps-big-blue?_pos=1&_sid=41ce0ba55&_ss=r cannonkeys.com]
|-
| Cherry || [[APL2]] || 🇺🇸 || [https://mykeyboard.eu/catalogue/pbt-crp-r4-alphas-apl_3957/ mykeyboard.eu]
|-
| Cherry || Dyalog || 🇺🇸 || [https://novelkeys.com/products/cherry-olivia?variant=43001363431591 NovelKeys]
|-
! Key stickers
| any || Dyalog || 🇺🇸 || [https://www.tindie.com/products/russtopia/apl-keyboard-symbol-sticker-set/ Tindie]
|}

Note that these devices only are visual modifications on regular keyboards; they do not automatically enable entry of APL glyphs into software. For this, one of the below methods is required.

== By platform ==

[[File:Adám Brudzewsky's in-browser language bar.png|thumb|right|The in-browser language bar]]
=== Web ===

* [[Adám Brudzewsky]]'s [https://abrudz.github.io/lb/apl  in-browser language bar] adds APL keyboard functionality to most web pages on demand.

* [https://daveremba.com/apl_vk_demo/  APL VK] is a virtual keyboard for the APL Language for modern mobile devices. You can add this to your own web page to provide a means to enter APL symbols into a web based form or editor. It is similar to the APL language bar but is optimized for mobile devices.

=== Text editors ===
{{Main|Text editors}}
Keyboard layout extensions exist for several popular text editors like VS Code, Emacs and Vim. This can be an alternative, or complementary, to system-wide settings.

=== Linux ===
{{Main|Typing glyphs on Linux}}

* Most Linux distributions released after mid-2012 have Dyalog shifting-key support included with the distribution.

* [https://github.com/secwang/espanso-apl-keyboard espanso-apl-keyboard] provides text replacement entry.

[[File:Array Hacker's Keyboard.png|thumb|right|Array Hacker's Keyboard]]

=== Android ===

* dzaima's [https://github.com/dzaima/hackerskeyboard Array Hacker's Keyboard] uses a [[wikipedia:Pointing_device_gesture#Touchpad_and_touchscreen_gestures|long-press]] to access APL glyphs.

* Optima Systems' [https://play.google.com/store/apps/details?id=com.athoraya.aplkeys APL Keys] provides both QWERTY keyboard (which uses long-press to select from a list of alternate glyphs), a phone pad, and a symbol view.

=== Windows ===

* [[Adám Brudzewsky]] has [https://github.com/abrudz/Kbd various keyboard English layouts for Windows], which allow <kbd>AltGr</kbd> as shifting key, <kbd>`</kbd> as prefix key, or ASCII symbol composition.

* [https://github.com/secwang/espanso-apl-keyboard espanso-apl-keyboard] provides text replacement entry.

* The [https://www.dyalog.com/apl-font-keyboard.htm#tab-1 Dyalog Unicode IME] uses <kbd>Ctrl</kbd>. Unless unselected, this [[wikipedia:Input_method|IME]] is installed by default with [[Dyalog APL]]:<br>[[File:Dyalog_APL_Installer.png|frameless|Dyalog APL IME selected in installer]]

* [https://github.com/Dyalog/APLAutoHotKey APLAutoHotKey] is an application to produce configurable AutoHotKey scripts for shifting key input.

* e-sushi has  [https://github.com/e-sushi/aplhotstrings/tree/main an AutoHotkey script] that allows ASCII composition.

==== Troubleshooting ====
Installation of the Dyalog Unicode IME can cause so many layouts to be installed that they get in the way when switching layouts. However, the unneeded layouts can be removed through editing the registry<ref>Chan, Vince. [https://forums.dyalog.com/viewtopic.php?f=14&t=1815&p=7164#p7164 How to remove Dyalog APL IME from various languages (MS WIN)]. Dyalog Forums. November 3, 2021.</ref>

=== macOS ===
* [https://github.com/secwang/espanso-apl-keyboard espanso-apl-keyboard] provides text replacement entry.

To enable these keyboard key mappings on [[wikipedia:macOS|macOS]], the appropriate <code>.keylayout</code> files for your locale must be downloaded and installed in the <code>/Library/Keyboard Layouts</code> directory:

* [[Dyalog Ltd.]] provides keyboard layouts for [https://www.dyalog.com/uploads/files/download.php?file=DyalogAltDK.zip Danish], [https://www.dyalog.com/uploads/files/download.php?file=DyalogAltIT.zip Finnish], [https://www.dyalog.com/uploads/files/download.php?file=DyalogAltIT.zip Italian], [https://www.dyalog.com/uploads/files/download.php?file=DyalogAltUK.zip British], and [https://www.dyalog.com/uploads/files/download.php?file=DyalogAltUS.zip American]. 

* LdBeth provides a keyboard layout for [https://github.com/LdBeth/APL-JIS Japanese (JIS)].

* [https://aplwiki.com/wiki/Typing_glyphs#ASCII_symbol_composition ASCII symbol composition] US and UK layouts are available from [https://github.com/abrudz/kbd#ascii-symbol-composition-layouts github.com/abrudz/kbd].

=== iOS ===

* ohAitch's [https://github.com/ohAitch/APLiOS APLiOS], aimed primarily at iPadOS, provides a number bar and APL symbol layers.

* [https://github.com/gitonthescene/APLKeyboard APLKeyboard] is built with [http://omz-software.com/pythonista/ Pythonista's] keyboard extension.  The keys are a bit small but it's functional.

== By method ==

Most of today's APLs use a mapping which derives from the original [[APL\360]] terminals' keyboard layout. For example, Dyalog APL's standard US English layout for is as follows:
<pre>
┌────┬────┬────┬────┬────┬────┬────┬────┬────┬────┬────┬────┬────┬─────────┐
│~ ⌺ │! ⌶ │@ ⍫ │# ⍒ │$ ⍋ │% ⌽ │^ ⍉ │& ⊖ │* ⍟ │( ⍱ │) ⍲ │_ ! │+ ⌹ │Backspace│
│` ⋄ │1 ¨ │2 ¯ │3 < │4 ≤ │5 = │6 ≥ │7 > │8 ≠ │9 ∨ │0 ∧ │- × │= ÷ │         │
├────┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬──────┤
│Tab    │Q   │W   │E ⍷ │R   │T ⍨ │Y   │U   │I ⍸ │O ⍥ │P ⍣ │{ ⍞ │} ⍬ │| ⊣   │
│       │q ? │w ⍵ │e ∊ │r ⍴ │t ~ │y ↑ │u ↓ │i ⍳ │o ○ │p * │[ ← │] → │\ ⊢   │
├───────┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴┬───┴──────┤
│Caps    │A   │S   │D   │F   │G   │H   │J ⍤ │K ⌸ │L ⌷ │: ≡ │" ≢ │Enter     │
│Lock    │a ⍺ │s ⌈ │d ⌊ │f _ │g ∇ │h ∆ │j ∘ │k ' │l ⎕ │; ⍎ │' ⍕ │          │
├────────┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──┬─┴──────────┤
│Shift      │Z ⊆ │X   │C   │V   │B   │N   │M   │< ⍪ │> ⍙ │? ⍠ │Shift       │
│           │z ⊂ │x ⊃ │c ∩ │v ∪ │b ⊥ │n ⊤ │m | │, ⍝ │. ⍀ │/ ⌿ │            │
└───────────┴────┴────┴────┴────┴────┴────┴────┴────┴────┴────┴────────────┘
</pre>
Additional charts for other layouts are [https://dfns.dyalog.com/n_keyboards.htm available].

There are multiple ways to access the glyphs associated with a particular key.

=== Shifting key ===

It is quite common to use <kbd>Ctrl</kbd> or <kbd>Alt</kbd> or <kbd>AltGr</kbd> (right-side <kbd>Alt</kbd>) as an additional shifting key. For example, <kbd>AltGr</kbd>+<kbd>4</kbd> would give <syntaxhighlight lang=apl inline>≤</syntaxhighlight> while <kbd>AltGr</kbd>+<kbd>Shift</kbd>+<kbd>4</kbd> would give <syntaxhighlight lang=apl inline>⍋</syntaxhighlight>.

* The [https://www.dyalog.com/apl-font-keyboard.htm#tab-1 Dyalog Unicode IME] uses <kbd>Ctrl</kbd>

* [[NARS2000]] uses <kbd>Alt</kbd>

* [[APLX]] uses <kbd>AltGr</kbd> with an option to also use <kbd>Alt</kbd>

=== Prefix key ===

A prefix key is a special key or character which is entered immediately before typing the corresponding key.

* [[TryAPL]] and [[ngn/apl]]'s scripted demo interface support <kbd>`</kbd> as prefix key.

* The [https://www.dyalog.com/apl-font-keyboard.htm#tab-1 Dyalog Unicode IME] and the [https://github.com/Dyalog/ride/releases/latest Dyalog RIDE] (Remote Integrated Development Environment) uses <kbd>`</kbd> by default, but allows choosing any key as prefix key.

* [[Adám Brudzewsky]]'s [https://abrudz.github.io/lb/apl in-browser language bar] recognises all the following as prefix keys: <kbd>`</kbd>, <kbd>½</kbd>, <kbd>²</kbd>, <kbd>^</kbd>, <kbd><s>º</s></kbd>, <kbd>§</kbd>, <kbd>ù</kbd>, <kbd>µ</kbd>, <kbd>°</kbd>.

* Custom .XCompose files can be used on Linux as described in [https://aplwiki.com/wiki/Typing_glyphs_on_Linux#XCompose_(backtick/prefix/dead_key) the page Typing Glyphs on Linux].

[[File:RIDE keyword lookup.png|thumb|right|RIDE keyword lookup]]

=== Long-press ===

dzaima's [https://github.com/dzaima/hackerskeyboard Hacker's Keyboard + APL language] reacts to a [[wikipedia:Pointing_device_gesture#Touchpad_and_touchscreen_gestures|long-press]], popping up a palette that allows selecting any of the APL glyphs associated with that button.

=== Keyword look-up ===

The [https://github.com/Dyalog/ride/releases/latest Dyalog RIDE] (Remote Integrated Development Environment) allows hitting the prefix key (<kbd>`</kbd> by default, but configurable) twice, followed by the (beginning of the) name of a symbol or a functionality. It then displays a drop-down of choices with arrow keys to indicate choice and the Tab key to insert the symbol. E.g. <kbd>`</kbd>,<kbd>`</kbd>,<kbd>d</kbd>,<kbd>i</kbd>,<kbd>v</kbd>,<kbd>Tab↹</kbd> inserts <syntaxhighlight lang=apl inline>÷</syntaxhighlight>.

=== ASCII symbol composition ===

Many APL glyphs can be approximated by overlaying or juxtaposing two ASCII characters. [[ngn/apl]]'s scripted demo interface, [https://abrudz.github.io/lb/apl Adám Brudzewsky's in-browser language bar], and [[TryAPL]]'s web interface allow such a pair of characters and hitting the <kbd>Tab↹</kbd> key to replace them with the corresponding APL character. For example, <kbd><</kbd>,<kbd>-</kbd>,<kbd>Tab↹</kbd> will insert <syntaxhighlight lang=apl inline>←</syntaxhighlight> and <kbd>T</kbd>,<kbd>o</kbd>,<kbd>Tab↹</kbd> will insert <syntaxhighlight lang=apl inline>⍕</syntaxhighlight>.

For Windows users, e-sushi has  [https://github.com/e-sushi/aplhotstrings/tree/main an AutoHotkey script] that allows such composition.

=== Text replacement ===

[https://github.com/espanso/espanso Espanso] allows typing a pattern which is then immediately replaced with something else. This can be used in various ways to type APL glyphs without conflicting with application or operating system keyboard shortcuts. [https://github.com/secwang/espanso-apl-keyboard espanso-apl-keyboard] is an Espanso configuration that emulates prefix key, so for example typing pressing <kbd>`</kbd>,<kbd>e</kbd> too type <code>`e</code> will be end up producing the <syntaxhighlight lang=apl inline>∊</syntaxhighlight> glyph.

[[File:NARS2000 language bar.png|thumb|right|NARS2000 language bar]]
=== On-screen language bar ===

Several APL IDEs allow the display of a toolbar with a button for each APL glyph:

* [[Dyalog APL]], [[NARS2000]], [[APL2]] and [[ngn/apl]]'s scripted demo interface  all have this feature.

=== LaTeX ===

In order to typeset APL using LaTeX, you need to be sure your LaTeX engine has full Unicode support. At the time of writing, LuaLaTeX and XeLaTeX are two of the most popular such alternatives, both included with TeX Live.

After ensuring you have a LaTeX engine that is Unicode capable, you need to make sure your .tex document is using a [[Fonts|font]] that has the APL glyphs you want to type. One way to do this is through the fontspec package, as seen in the example template below.

To check your setup is fully functional you can try compiling the following template:
[[File:LaTeX APL template.png|thumb|right|Screenshot of the typeset document]]
<syntaxhighlight lang=latex>
\documentclass[11pt]{article}

\usepackage{fontspec}
\setmainfont{APL385 Unicode}
\setmonofont{APL385 Unicode}[Scale=MatchLowercase]

\begin{document}

I just want some ← +-×÷*⍟⌹○!? |⌈⌊⊥⊤⊣⊢ =≠≤<>≥≡≢ ∨∧⍲⍱ ↑↓⊂⊃⊆⌷⍋⍒ ⍳⍸∊⍷∪∩~ /\textbackslash⌿⍀ ,⍪⍴⌽⊖⍉ ¨⍨⍣.∘⍤⍥@ ⍞⎕⍠⌸⌺⌶⍎⍕ ⋄⍝→⍵⍺∇\& ¯⍬

\texttt{The ``setmonofont'' was needed because of this, otherwise ⍺⌊¯→⍬ wouldn't show properly}.

\end{document}
</syntaxhighlight>

Depending on whether you want the whole document to use the APL font or not, you may remove the command to set the main font. If you do so, APL glyphs will be rendered correctly inside code listings and similar environments, but not in the main body of the document. 

==== Listings ====

LuaLaTeX and XeLaTeX can use the [https://en.wikibooks.org/wiki/LaTeX/Source_Code_Listings ''listings'' package] to include APL source with the following document preamble:<ref>Baker, John D. [https://analyzethedatanotthedrivel.org/2011/08/15/typesetting-utf8-apl-code-with-the-latex-lstlisting-package/ Typesetting UTF8 APL code with the LaTeX lstlisting package]. Analyze the Data not the Drivel. August 15, 2011.</ref>
<syntaxhighlight lang=latex>
% set lstlisting to accept UTF8 APL text
\makeatletter
\lst@InputCatcodes
\def\lst@DefEC{%
 \lst@CCECUse \lst@ProcessLetter
  ^^80^^81^^82^^83^^84^^85^^86^^87^^88^^89^^8a^^8b^^8c^^8d^^8e^^8f%
  ^^90^^91^^92^^93^^94^^95^^96^^97^^98^^99^^9a^^9b^^9c^^9d^^9e^^9f%
  ^^a0^^a1^^a2^^a3^^a4^^a5^^a6^^a7^^a8^^a9^^aa^^ab^^ac^^ad^^ae^^af%
  ^^b0^^b1^^b2^^b3^^b4^^b5^^b6^^b7^^b8^^b9^^ba^^bb^^bc^^bd^^be^^bf%
  ^^c0^^c1^^c2^^c3^^c4^^c5^^c6^^c7^^c8^^c9^^ca^^cb^^cc^^cd^^ce^^cf%
  ^^d0^^d1^^d2^^d3^^d4^^d5^^d6^^d7^^d8^^d9^^da^^db^^dc^^dd^^de^^df%
  ^^e0^^e1^^e2^^e3^^e4^^e5^^e6^^e7^^e8^^e9^^ea^^eb^^ec^^ed^^ee^^ef%
  ^^f0^^f1^^f2^^f3^^f4^^f5^^f6^^f7^^f8^^f9^^fa^^fb^^fc^^fd^^fe^^ff%
  ^^^^20ac^^^^0153^^^^0152%
  ^^^^20a7^^^^2190^^^^2191^^^^2192^^^^2193^^^^2206^^^^2207^^^^220a%
  ^^^^2218^^^^2228^^^^2229^^^^222a^^^^2235^^^^223c^^^^2260^^^^2261%
  ^^^^2262^^^^2264^^^^2265^^^^2282^^^^2283^^^^2296^^^^22a2^^^^22a3%
  ^^^^22a4^^^^22a5^^^^22c4^^^^2308^^^^230a^^^^2336^^^^2337^^^^2339%
  ^^^^233b^^^^233d^^^^233f^^^^2340^^^^2342^^^^2347^^^^2348^^^^2349%
  ^^^^234b^^^^234e^^^^2350^^^^2352^^^^2355^^^^2357^^^^2359^^^^235d%
  ^^^^235e^^^^235f^^^^2361^^^^2362^^^^2363^^^^2364^^^^2365^^^^2368%
  ^^^^236a^^^^236b^^^^236c^^^^2371^^^^2372^^^^2373^^^^2374^^^^2375%
  ^^^^2377^^^^2378^^^^237a^^^^2395^^^^25af^^^^25ca^^^^25cb%
  ^^00}
\lst@RestoreCatcodes
\makeatother
</syntaxhighlight>


==== Metafont ====
An APL metafont usable to typeset APL in LaTeX files is available on the ([https://ctan.org/pkg/apl?lang=en Comprehensive TeX Archive Network]), available for free use.
The version of the package is from 1987 and may not be suitable for glyphs used in modern APL implementations..

=== plainTeX ===

LdBeth has made a [https://ldbeth.sdf.org/aplfont.html Type1 version] of [https://github.com/rbanffy/3270font 3270 font] with APL support, suitable for traditional TeX implementations that cannot directly use TTF/OTF fonts.

[[File:3270 APL font sample.png|thumb|right|Screenshot of the typeset document]]
<syntaxhighlight lang=latex>
\input apldef.tex

\font\apl=3270

\apl

1234567890{\rm Good?}\NG1+2-3{\rm Mixing some roman}

I just want some \IS +-\ML\DV\ST\LG\DQ\LO{}!?\ |\CE\FL\DE\EN\LK\RK\ =\NE\LE<>\GE\EU\SE

\AD\OR\NA\NO\ \UA\DA\RU\LU\SS\SQ\GU\GD\ \IO\UI\EP\UE\UU\DU\NT\ /\BL\CS\CB\ ,\BC\RO\RV\CR\TR

\DD\RR\PP.\SO\RN\OV{}@\ \QQ\BX\CQ\EQ\MQ\IB\XQ\FM\ \DM\LM\GO\OM\AM\DL\&

\NG\NL

\obeylines\DL S\IS SUM N;I
S\IS I\IS 0
\GO (N<I\IS I+1)/0
S\IS S+I\ST 2
\GO 2
\DL
\bye
</syntaxhighlight>

== References ==
<references/>
{{APL development}}
{{APL glyphs}}
[[Category:APL character set]][[Category:Lists]]