This repository contains:

• wayland-scanner-jai, a Jai implementation of wayland-scanner which emits Jai code
• Wayland protocol bindings for Jai
• XKB bindings for Jai

Bindings provided with this repo are for client code. If you want server code, you need to generate this yourself. See Generation below for more.

Client bindings were generated against:

• Wayland version 1.22.0-2.1build1
• libxkbcommon version 1.6.0-1build1

These bindings require libwayland-client.so.0 (and libwayland-server.so.0, but this is assumed to come with client installations) and libxkbcommon.so.0 to exist in your system library search path. Usage assumes that your window manager is actually using Wayland.

Clone this repo into a folder in your modules path, say Wayland. Then,

Wayland :: #import "Wayland";

// Call the following before using any other code from the bindings.
Wayland.init_wayland_protocol_bindings();

Note that the Wayland protocol definitions in C have global variable identifiers share names with their corresponding struct types at times. The same goes for enums. Jai does not allow this, so we need to disambiguate. Enum definitions are given a _e suffix, and *_interface global instances of structs are given a _instance suffix. You can see what this looks like in practice in example.jai.

If you want to use wayland-scanner-jai standalone, compile it (see Generation below) and then run it to see its help text.

When generating Wayland protocol code and bindings, it is often convenient to process multiple XML files at once so that all the protocol code you need is emitted in the single output file. (See the example in Testing below.) When doing this, opaque type declarations will often be duplicated across protocol definitions. In this case, pass the --dont-emit-opaque-decls command-line argument and add the opaque type declarations yourself in supporting code.

Unlike in C, in Jai, there are some assignments to globally-scoped variables in the Wayland protocol code that cannot be done at compile time. Therefore, you must call init_wayland_protocol_bindings() (defined for you in the output of this tool) in your code before using anything else from the generated code.

To build a Wayland application, you will also need to supplement this tool's output with fundamental Wayland type definitions generated from Wayland headers. Such supporting code is included in the complete bindings produced via generate.jai. Again, see Generation for more.

You can build and run an example that uses the generated bindings.

jai example.jai
./example

The example runs at ~60 fps, renders a small window with a light blue background, and can be terminated by pressing the Escape key. Key strokes captured by the window are printed to the terminal.

First, compile wayland-scanner-jai:

jai wayland-scanner-jai.jai

If you don't already have it, install the Wayland dependencies and xkb development libraries. On systems with the apt package manager:

sudo apt install wayland-protocols libwayland-dev libxkbcommon-dev

Finally, generate the bindings. Note that you may have to tune the opaque type declarations in module.jai depending on the set of Wayland XML protocol definitions you generate code from. The generator expects protocol definitions, Wayland headers, and xkb headers to exist in specific locations on your system and Wayland and xkb libraries be discoverable on the library search path. To see which XML files the generator is using, inspect generate.jai.

jai generate.jai - client

Note the help text of the generator:

usage: jai generate.jai [...] - [{client|server}]

Options:
  {client|server}    Generate bindings for client or server applications. If
                     not provided, the tool generates bindings for clients.

Compile and run test.jai. At this time, this tests the built-in XML parser used to parse Wayland XML protocol definitions.

To exercise wayland-scanner-jai and generate protocol code for the fundamental Wayland client protocol, the xdg-shell protocol, and the xdg-decoration protocol, run the following with paths adapted to your needs:

jai wayland-scanner-jai.jai
./wayland-scanner-jai client --dont-emit-opaque-decls \
  /usr/share/wayland-protocols/stable/xdg-shell/xdg-shell.xml \
  /usr/share/wayland-protocols/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml \
  /usr/share/wayland/wayland.xml