ZKeymap (WIP)

March 31, 2025 · View on GitHub

Python DSL for ZMK Keymaps definitions and files generation.

This tool can generate keymaps, transoforms and layouts in json and svg formats.

Motivation

While I still prefer text-based layout definitions over graphical editors, devicetree syntax seems overly complicated. As a result, I created this small language to enable easy and pleasant keymap definitions for ZMK, eliminating the need for graphical editors.

Big Note

You can use unicode chars directly as aliases, it looks good and works well but it is totally optional. All aliases are user defined or can be overridden by the user.

Usage

1. Install zkeymap

pip install zkeymap

2. Add a python file to your config directory, for example `mykeymap.py`

3. Write your keymap in zkeymap language, here is an example `splitkb.py`:

src/zkeymap/demo/splitkb.py

4. Generate your devicetree files:

python3 mykeymap.py

That will generate four files as per the example:

File	Content	Format
splitkb_keymap.dtsi	Keymap, macros, dances, encoders	devicetree
splitkb_transform.dtsi	zmk,matrix-transform	devicetree
splitkb_layout.dtsi	zmk,physical-layout	devicetree
splitkb_info.json	physical layout	QMK info.json
splitkb_layout.svg	Graphical layout (built-in generator)	svg
splitkb_drawer.svg	Graphical layout (keymap-drawer generator)	svg
splitkb_switches_layout.svg	Graphical layout for switches holes	svg

5. Then in your zmk keymap file remove the keymap node and include the generated file example:

#include <behaviors.dtsi>
#include <dt-bindings/zmk/keys.h>
#include <dt-bindings/zmk/bt.h>
#include <dt-bindings/zmk/ext_power.h>
#include <dt-bindings/zmk/outputs.h>
#include <dt-bindings/zmk/matrix_transform.h>

// +------------------------------------+
// | Include the generated keymap here: |
// +------------------------------------+
#include "splitkb_keymap.dtsi"
#include "splitkb_transform.dtsi"
#include "splitkb_layout.dtsi"

/ {

    chosen {
        zmk,kscan = &kscan0;
        zmk,matrix-transform = &marz_split_3x6_4_transform;
        zmk,physical-layout = &marz_split_3x6_4;
    };

    kscan0: kscan {
        compatible = "zmk,kscan-gpio-matrix";
        label = "KSCAN";

        diode-direction = "col2row";
        wakeup-source;

        row-gpios
            = <&pro_micro 4 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
            , <&pro_micro 5 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
            , <&pro_micro 6 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
            , <&pro_micro 7 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
            ;

    };


};

Commit and push your changes as usual to built the firmware.

Basic language rules

Everything is based around aliases, you define an alias mapping any char (even unicode chars) to ZML Keys or macros or whatever.

Depending on how you decorate the alias, it will be translated into a specific behavior (&lt, &mo, &to, &kp, etc...)

Aliases definitions

To define an alias just express it like this:

alias / "alias" / "translation"

Example: define symbol ⌘ as an alias of LGUI:

alias / "⌘" / "LGUI"

Then you can use ⌘ in the keymap as [ ⌘ ] it will be translated to &kp LGUI

Key press (&kp, &sk)

Square brackets syntax [ alias ].

Example: Where a is an alias and X is the alias resolution

syntax	compiles to	Notes
[ a ]	&kp X	Simple case
[ shift a ]	&kp LS(X)	With shift mods
[ ⎈ a ]	&kp LC(X)	With Ctrl mods
[ r⇧ ⎈ a ]	&kp RS(LC(X))	With RShift+LCtrl mods

For a sticky key variation, just add ~ at the end and &kp will be changed to &sk

syntax	compiles to	Notes
[ lshift ~]	&sk LSHIFT	One shot/sticky Shift

Mod-Tap behavior (&mt)

Curly brackets syntax { mod alias }.

Example: Where a is an alias and X is the alias resolution.

syntax	compiles to	Notes
{ shift a }	&mt LSHIFT X	hold=lshift, tap=X
{ ⎈ a }	&mt LCTRL X	hold=lctrl, tap=X
{ r⇧ a }	&mt RSHIFT X	hold=rshift, tap=X

Layer based behaviors (&lt, &mo, &sl, &to, &tog)

Parenthesis syntax ( layer alias ).

Example: Where LAY is a layer, a is an alias and X is the alias resolution.

syntax	compiles to	Notes
( LAY )	&mo LAY	momentary layer
( LAY a )	&lt LAY X	layer tap LAY and X
( LAY / ~ )	&lt LAY TILDE	layer tap LAY and ~
( LAY ~)	&sl LAY	sticky layer LAY. See the difference with previous
( LAY !)	&to LAY	absolute layer LAY
( LAY /)	&tog LAY	toggle layer LAY

Raw ZMK stuff

Triangle brackets syntax < whatever >.

Content inside < and > is resolved to raw ZMK code.

Example:

syntax	compiles to	Notes
	A	raw zmk code
<&lt 1 A>	&lt 1 A	raw zmk code
<&caps_word>	&caps_word	raw zmk code
<&kp LCTRL>	&kp LCTRL	raw zmk code

Macros

Definitions of macros is done using aliases:

alias / "hello" / macro("[shift h] e l l o")

Then it can be used in a layer:

layer / "def" / r""" hello """

Unicode

A special case for Unicode macros allows to define lower and upper variations:


alias / "∴" / uc(name="t3p", char="∴", shifted="△")

layer / "def" / r""" [ ∴ ] """

In this case [ ∴ ] will be translated to ∴ on tap and to △ on Shift tap.

Status

This project is quite new and experimental, testers and contributors are welcome.

Key areas of contribution:

Documentation
Aliases for different languages/layouts.
Unit tests
Reporting bugs

Common Unicode chars for keyboards

LEFT	RIGHT	UNICODE	DESCRIPTION
⌘	r⌘	u2318	GUI/Command
⎈	r⎈	u2388	Ctrl
⇧	r⇧	u21E7	Shift
⎇	r⎇	u2387	Alt
⏎		u23CE	Enter
␣		u2423	Space
⌫		u232b	Backspace
←		u2190	Arrow Left
↑		u2191	Arrow Up
→		u2192	Arrow Right
↓		u2193	Arrow Down
ᛒ		u16D2	Bluetooth
⇪		u21EA	CapsLock
🄰		u1F130	CapsLock
⎙		u2399	PrintScreen
⇄		u21C4	Tab
↖		u2196	Home
↘		u2198	End
⇞		u21DE	PgUp
⇟		u21DF	PgDn
↶		u21B6	Undo
↷		u21B7	Redo
✂		u2702	Cut
⿻		u2FFb	Copy
⧉		u29c9	Paste
⚙		u2699	Bootloader

Working examples

https://github.com/mnesarco/zmk-config

AI Usage

Codeium AI was used to generate docstrings and basic unit tests.