Add Zig to your CMake Project

README.md

First add your build.zig file to your project source directory. Then add these 2 files alongside each other wherever you keep your cmake include files:

Zig.cmake:

execute_process(
    COMMAND ${CMAKE_CURRENT_LIST_DIR}/install-zig
    OUTPUT_VARIABLE ZIG_EXE
    RESULT_VARIABLE INSTALL_ZIG_EXIT_CODE
)
if (NOT INSTALL_ZIG_EXIT_CODE EQUAL "0")
    message(FATAL_ERROR "install-zig failed")
endif()
add_custom_target(zigbuild
    COMMAND "${ZIG_EXE}" build --prefix ${CMAKE_CURRENT_BINARY_DIR}
    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
    DEPENDS ${PROJECT_SOURCE_DIR}/build.zig
)

install-zig:

#!/usr/bin/env python3
# TODO: add windows support
import os
import sys
import fcntl
import shutil
import subprocess

ZIG_VERSION = "0.10.0-dev.2463+b095aa698"
ZIG_INSTALL_PATH = os.path.join(os.getenv("HOME"), ".zig-cmake")

def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)

def run(*args, **kwargs):
    eprint("[RUN] " + subprocess.list2cmdline(*args))
    sys.stdout.flush()
    return subprocess.check_call(*args, **kwargs)

def download(url, filename):
    tmp_filename = filename + ".downloading"
    if os.path.exists(tmp_filename):
        os.remove(tmp_filename)
    run(["curl", url, "--output", tmp_filename])
    os.rename(tmp_filename, filename)

def get_zig_platform():
    import platform
    if sys.platform.startswith("linux"):
        return "linux-x86_64"
    if sys.platform.startswith("darwin"):
        if platform.processor().startswith("arm"):
            return "macos-aarch64"
        return "x86_64"
    sys.exit("unknown platform '{}'".format(sys.platform))

def main():
    ZIG_INSTALL_PATH = os.path.join(os.getenv("HOME"), ".zig-cmake", "zig")
    if not os.path.exists(ZIG_INSTALL_PATH):
        os.makedirs(ZIG_INSTALL_PATH)

    lock_file_path = os.path.join(ZIG_INSTALL_PATH, ".lock")
    lock_file = open(lock_file_path, "w")
    fcntl.flock(lock_file.fileno(), fcntl.LOCK_EX)

    version_install_path = os.path.join(ZIG_INSTALL_PATH, ZIG_VERSION)
    if not os.path.exists(version_install_path):
        zig_platform = get_zig_platform()
        archive_root_basename = "zig-" + zig_platform + "-" + ZIG_VERSION
        tar_basename = archive_root_basename + ".tar.xz"
        tar_path = os.path.join(ZIG_INSTALL_PATH, tar_basename)
        download("https://ziglang.org/builds/" + tar_basename, tar_path)

        extract_root_dir = os.path.join(ZIG_INSTALL_PATH, archive_root_basename)
        if os.path.exists(extract_root_dir):
            shutil.rmtree(extract_root_dir)
        run(["tar", "-C", ZIG_INSTALL_PATH, "-xf", tar_path])
        os.remove(tar_path)
        os.rename(extract_root_dir, version_install_path)
    print(os.path.join(version_install_path, "zig"), end='')

main()

Then you can include the Zig.cmake file and declare zig output dependencies via:

include(Zig)
# let cmake know what files we use from zigbuild
add_custom_command(
    DEPENDS zigbuild
    OUTPUT
        ${CMAKE_CURRENT_BINARY_DIR}/PUT_YOUR_ZIG_OUT_FILES_HERE
)

Also remember to add your zig output files as dependencies to any other cmake component.