Python: Add wrapper for Slint Compiler

This permits invoking the Slint compiler conveniently via `uvx
slint-compiler` or `pipx slint-compiler`.

cc #4136

api/python/compiler/.gitignore

@@ -0,0 +1 @@
+*.egg-info

api/python/compiler/README.md

@@ -0,0 +1,15 @@
+<!-- Copyright © SixtyFPS GmbH <info@slint.dev> ; SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0 -->
+
+# Python Slint Compiler
+
+This package is a wrapper around [Slint's](https://slint.dev) compiler for Python, to generate a typed `.py` file from a `.slint` file, for use with [Slint for Python](https://pypi.org/project/slint/).
+
+When run, the slint compiler binary is downloaded, cached, and run.
+
+By default, the Slint compiler matching the version of this package is downloaded. To select a specific version, set the `SLINT_COMPILER_VERSION` environment variable. Set it to `nightly` to select the latest nightly release.
+
+## Example
+
+```bash
+uxv run slint-compiler -f python -o app_window.py app-window.slint
+```

api/python/compiler/pyproject.toml

@@ -0,0 +1,13 @@
+# Copyright © SixtyFPS GmbH <info@slint.dev>
+# SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
+
+[project]
+name = "slint-compiler"
+version = "1.12.1b1"
+description = "Python wrapper around the Slint compiler for Python"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = ["cached-path>=1.7.3"]
+
+[project.scripts]
+slint-compiler = "slint_compiler:main"

api/python/compiler/slint_compiler/__init__.py

@@ -0,0 +1,67 @@
+# Copyright © SixtyFPS GmbH <info@slint.dev>
+# SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
+
+import cached_path
+import platform
+import sys
+import subprocess
+import re
+import os
+from importlib.metadata import version, PackageNotFoundError
+
+
+def main():
+    try:
+        package_version = version("slint-compiler")
+        # Strip alpha/beta from for example "1.13.0b1"
+        version_regex = re.search("([0-9]*)\\.([0-9]*)\\.([0-9]*).*", package_version)
+        assert version_regex is not None
+        major = version_regex.group(1)
+        minor = version_regex.group(2)
+        patch = version_regex.group(3)
+        github_release = f"v{major}.{minor}.{patch}"
+    except PackageNotFoundError:
+        github_release = "nightly"
+
+    # Permit override by environment variable
+    github_release = os.environ.get("SLINT_COMPILER_VERSION") or github_release
+
+    operating_system = {
+        "darwin": "Darwin",
+        "linux": "Linux",
+        "win32": "Windows",
+        "msys": "Windows",
+    }[sys.platform]
+    arch = {
+        "aarch64": "aarch64",
+        "amd64": "x86_64",
+        "arm64": "aarch64",
+        "x86_64": "x86_64",
+    }[platform.machine().lower()]
+    exe_suffix = ""
+
+    if operating_system == "Windows":
+        arch = {"aarch64": "ARM64", "x86_64": "AMD64"}[arch]
+        exe_suffix = ".exe"
+    elif operating_system == "Linux":
+        pass
+    elif operating_system == "Darwin":
+        arch = {"aarch64": "arm64", "x86_64": "x86_64"}[arch]
+    else:
+        raise Exception(f"Unsupported operarating system: {operating_system}")
+
+    platform_suffix = f"{operating_system}-{arch}"
+    prebuilt_archive_filename = f"slint-compiler-{platform_suffix}.tar.gz"
+    download_url = f"https://github.com/slint-ui/slint/releases/download/{github_release}/{prebuilt_archive_filename}"
+    url_and_path_within_archive = f"{download_url}!slint-compiler{exe_suffix}"
+
+    local_path = cached_path.cached_path(
+        url_and_path_within_archive, extract_archive=True
+    )
+    args = [local_path]
+    args.extend(sys.argv[1:])
+    subprocess.run(args)
+
+
+if __name__ == "__main__":
+    main()