Typing glyphs on Linux

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Revision as of 12:13, 18 January 2021 by RichPark (talk | contribs) (Add guide for Wayland (tested on default Fedora 33 installation))
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Since mid-2012, most Linux distributions with X11 have Dyalog APL keyboard support included with the distribution,[1] using xkb, the X Keyboard Extension.[2]


The simplest way to set up an APL keyboard on Linux is with the following setxkbmap command. Enter the following in your terminal emulator of choice:

setxkbmap -layout us,apl -variant ,dyalog -option grp:switch

An explanation:

  • -layout us,apl assigns us (U.S. English) to be the primary layout, whereas apl is secondary
  • -option grp:switch assigns Right Alt to switch to the secondary apl layout when it is pressed, otherwise us is used
  • -variant ,dyalog assigns the Dyalog APL variant to the apl layout which contains modifiations unique to the Dyalog language (Note the preceding comma)

A full list of keys that can be used to switch layouts is included in /usr/share/X11/xkb/rules/evdev.lst under the option category.

Note: these changes are not permanent; the user will have to select one of a myriad of methods to run the command on startup. Alternatively, if they use one of the desktop environments listed below, they can follow those instructions.



  1. Open the Activities menu; this is located in the top-left corner of a default GNOME 3 session (alternatively, use your Super key to open the Activities overlay):
    GNOME Keyboard Step 1: Open Activities Menu
  2. Search for "startup." When the Startup Applications program is highlighted, press the Enter key to open it:
    GNOME Keyboard Step 2: Search for Startup Applications
  3. Select the Add button on the right-hand side:
    GNOME Keyboard Step 3: Click the Add button in Startup Applications window
  4. Provide a name, enter your setxkbmap command, and click Add when finished:
    GNOME Keyboard Step 4: Enter the relevant information for your command


  1. Navigate to ~/.config/autostart and create a .desktop with any name that will help you remember its function.
  2. Add the following to the contents of your file, customizing to suit your needs:
    [Desktop Entry]
    Exec=setxkbmap -layout us,apl -variant ,dyalog -option grp:switch


  1. Prepend an @ to the setxkbmap command from above:
    @setxkbmap -layout us,apl -variant ,dyalog -option grp:switch
  2. Add it as a line in your user's LXDE autostart file, located at:

For Lubuntu versions up to and including 18.04 (before the LXQt split), the location of autostart is ~/.config/lxsession/Lubuntu/autostart.



  1. From your LXQt panel, navigate to PreferencesLXQt SettingsSession Settings; alternatively, enter lxqt-config-session in your terminal emulator. You will be greeted with the following window:
    LXQt Autostart menu of Session Settings window
  2. Select the LXQt Autostart dropdown (it will be highlighted as shown above) and click the Add button to display the following pop-up window:
    LXQt add a new autostart menu item
  3. Provide a name, enter your setxkbmap command, and click OK when finished.


The above GUI approach merely creates a .desktop file in the user's ~/.config/autostart. Create your own file in the autostart directory whose contents are as follows, to replicate the functionality achieved through the GUI:

[Desktop Entry]
Exec=setxkbmap -layout us,apl -variant ,dyalog -option grp:switch



  1. Open your MATE menu (in the top-left corner of a default environment) and select Control Center at the bottom of the window:
    Launch the Control Center from the MATE menu
  2. Scroll down through the main window, and under the Personal category, select Startup Applications:
    Scroll down to the Startup Applications option
  3. Click the Add button on the right-hand side:
    Click Add to add a new startup command
  4. Provide a name, enter your setxkbmap command, and click Add when finished:
    Enter the setxkbmap command you wish to use


Navigate to ~/.config/autostart and create a .desktop with any name that will help you remember its function.

Add the following to the contents of your file, customizing to suit your needs:

[Desktop Entry]
Exec=setxkbmap -layout us,apl -variant ,dyalog -option grp:switch


Currently, Wayland uses XKB for keyboards, but they are not modifiable during runtime using e.g. setxkbmap by default. The keyboard layout must be configured and then the session restarted.

GNOME Tweaks

The Tweaks tool allows configuration beyond the defaults enabled in GNOME.

  1. Install GNOME Tweaks using apt or dnf, or by searching your distribution's Software Center.
  2. Start GNOME Tweaks by either:
    1. Using a terminal, type gnome-tweaks and press Enter.
    2. Using the GUI:
      1. Open the Activities menu; this is located in the top-left corner of a default GNOME 3 session (alternatively, use your Super key to open the Activities overlay):
        Wayland Keyboard set up with GNOME Tweaks Step 2.1: Open Activities Menu
      2. Search for "Tweaks"
        Wayland Keyboard set up with GNOME Tweaks Step 2.2: Start GNOME Tweaks
  3. Open Keyboard & Mouse Panel and enable "Show Extended Input Sources"
    Wayland Keyboard set up with GNOME Tweaks Step 3: Open Keyboard & Mouse Panel
  4. Open the Additional Layout Options and tick one or more of the options under "Switching to another layout"
    Wayland Keyboard set up with GNOME Tweaks Step 4: Open Additional Layout Options
  5. Go to Settings → Region & Language → Add a new input source. Both English (United Kingdom) and English (United States) will have several APL layout options to choose from.
  6. Restart the session (for example, by logging out and logging in again).


Xfce's GUI (Settings ManagerKeyboardLayout) is unable to set up an APL-compatible keyboard. Therefore, we must do it ourselves.

Xfce ships with a utility, xfconf-query, which allows you to manage Xfce's XML configuration files on the command line. Enter the following commands into your terminal:

xfconf-query -c keyboard-layout -n -p '/Default/XkbDisable' -t 'bool' -s 'false'

This enables XKB, allowing us to manage our keyboard layout.

xfconf-query -c keyboard-layout -n -p '/Default/XkbLayout' -t 'string' -s 'us,apl'

Defines the keyboard layout itself. The comma-delimited apl specifies a second layout group. Make sure you replace us with the code for your language; a list of these can be found in /usr/share/X11/xkb/rules/evdev.lst, under the layout category.

xfconf-query -c keyboard-layout -n -p '/Default/XkbOptions/Group' -t 'string' -s 'grp:win_switch'

This tells Xfce to switch to the APL layout only when the Windows key is pressed. When the Windows key is released, the layout will return to its previous setting. This is incredibly useful as the apl layouts in XKB do not support Space, Enter, or the arrow keys (among basically all the others). A full list of possible keys for switching between keyboard groups is located in /usr/share/X11/xkb/rules/evdev.lst, under the option category.

xfconf-query -c keyboard-layout -n -p '/Default/XkbVariant' -t 'string' -s ',dyalog'

Specifies that the variant applies to the second layout, apl, due to the preceding comma. The dyalog variant is unique to Dyalog.

And you're done! Try holding down the Windows key and pressing H on your keyboard — you should see a .


Dyalog Overrides Current Keyboard Settings

By default, Dyalog APL overrides the current XKB configuration to use the Meta ("Windows") key as the modifier for entering APL symbols. If the user manages their keyboard configuration manually using the techniques described on this page, this behavior can be quite troublesome.

To run Dyalog in the terminal without overriding ("hijacking") the user keyboard configuration, run dyalog with the -nokbd option:

dyalog -nokbd

The following script can be used to launch RIDE, immediately connecting a new Dyalog instance, without changing the xkb settings:

#!/usr/bin/env sh
env RIDE_CONNECT=localhost:4502 ride &
dyalog +s -q -nokbd RIDE_INIT=SERVE:*:4502

The keyboard layout changing is done by the file at /opt/mdyalog/*/64/unicode/aplkeys.sh, so changing it changes the behavior (clearing it entirely stops the automatic keyboard layout switching). Note that the file exists for each installed version and is reset on any update, so it may need to be modified multiple times.

APL Keyboard Remains After Dyalog is Closed

Dyalog overrides the current keyboard configuration, as described in this section, but fails to return the user to their previous keyboard configuration on exit. To solve this, create a custom Bash script to save and revert keyboard settings upon exiting Dyalog APL:[3]

OLDLAYOUT=$(setxkbmap -query | sed -n 's/^layout://p')
OLDVARIANT=$(setxkbmap -query | sed -n 's/^variant://p')
OLDOPTION=$(setxkbmap -query | sed -n 's/^options://p')
OLDLAYOUT=$(echo $OLDLAYOUT | sed 's/^$/,/')
OLDVARIANT=$(echo $OLDVARIANT | sed 's/^$/,/')
setxkbmap -layout $OLDLAYOUT -variant $OLDVARIANT -option -option $OLDOPTION

Settings reverted during X Windows session

Since at least March 2020 there have been issues with setxkbmap settings being reset without user instruction under the X Windows System.

Below is a script written in Raku that continuously checks for this undesirable reset behavior and puts the intended settings back in place.[4]

#!/usr/bin/env raku

# Small script to ensure that APL keyboard layout is still set in xkb settings.
# Note that this is a patch for some sort of deranged time-based reset of these
# settings that is happening at a lower level of the Xorg-based Linux user experience.
# It's not clear what is causing these resets but this script allows us to more
# or less not care about it and get on with our hacking.
# Released under Artistic License by John Longwalker 2020

my $total-checks = 0;
sub xkbmap-contains-apl() {
  so qx{ setxkbmap -query | grep '^layout:.*\<apl\>' }; # shell-out is easy as usual in a Perl

my $total-resets = 0;
sub set-xkbmap-for-apl($key, $verbose) {
  say "Reset total is now {++$total-resets} -- {DateTime.now}"
  	if $verbose;
  my $xkb-settings = chomp qx{ setxkbmap -query };

  my ($layout, $variant, $options);
  if $xkb-settings ~~ /^^ "layout:" \s* $<layout>=(<.graph>*) $$/ {
  	$layout = $<layout>.Str;
  } else {
  	die "Aborting. The xkb settings do not specify any layout:\n$xkb-settings";

  if $xkb-settings ~~ /^^ "variant:" \s* $<variant>=(<.graph>*) $$/ {
  	$variant = $<variant>.Str;

  if $xkb-settings ~~ /^^ "options:" \s* $<options>=(<.graph>*) $$/ {
  	$options = $<options>.Str;

  $layout  = ($layout, 'apl').join(',');
  $variant = $variant ?? ($variant, 'dyalog')
                      !! 'dyalog';
  $options = $options ?? ($options, "grp:$key").join(',') 
                      !! "grp:$key";
  my $invocation = "setxkbmap -layout $layout -variant $variant -option $options";
  say "Invocation: $invocation"
    if $verbose;
  qqx{ $invocation };

# You can use --interval, --key, and -v/--verbose on the command line.
sub MAIN(:$interval = 30, :$key = 'switch', :v($verbose) = False) {
  react {
    whenever Supply.interval($interval) {
      set-xkbmap-for-apl($key, $verbose)
        if not xkbmap-contains-apl;

    whenever signal(SIGINT) {
      say "Reset a total of $total-resets out of $total-checks checks"
      	if $verbose;


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