René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Rethinking __init__ of VersionInfo class?","articleBody":"# Situation\r\n\r\n_Originally posted by @tomschr in https://github.com/python-semver/python-semver/issues/258#issuecomment-652482631_\r\n\r\nFrom the above discussion, I thought it would be worth to decouple the `compare` discussion from the initializer discussion. Both are somewhat related, but can live independently. \r\n\r\nWith a more \"advanced\" initializer/constructor we get the following benefits:\r\n\r\n* more \"pythonic\": it's one, obvious way to get an instance.\r\n* avoids the longer function call `Version.parse(...)`.\r\n* more readable\r\n\r\nWith such an (overloaded?) initializer, we could cover the following use cases:\r\n\r\n```python\r\n\u003e\u003e\u003e from semver import Version\r\n\u003e\u003e\u003e Version(1)\r\nVersion(major=1, minor=0, patch=0, prerelease=None, build=None)\r\n\u003e\u003e\u003e Version(1, \"4\", b\"5\")\r\nVersion(major=1, minor=4, patch=5, prerelease=None, build=None)\r\n\u003e\u003e\u003e Version(1, patch=2)\r\nVersion(major=1, minor=0, patch=2, prerelease=None, build=None)\r\n\u003e\u003e\u003e Version(\"1.2.3\")\r\nVersion(major=1, minor=2, patch=3, prerelease=None, build=None)\r\n\u003e\u003e\u003e Version(b\"1.2.3\")\r\nVersion(major=1, minor=2, patch=3, prerelease=None, build=None)\r\n\u003e\u003e\u003e v = Version(b\"2.3.4\")\r\n\u003e\u003e\u003e Version(v)\r\nVersion(major=2, minor=3, patch=4, prerelease=None, build=None)\r\n\u003e\u003e\u003e t = (1, 2, 3)\r\n\u003e\u003e\u003e Version(*t)                                             \r\nVersion(major=1, minor=2, patch=3, prerelease=None, build=None)\r\n\u003e\u003e\u003e d = {'major': 3, 'minor': 4, 'patch': 5,  'prerelease': 'pre.2', 'build': 'build.4'}\r\n\u003e\u003e\u003e Version(**d)\r\nVersion(major=3, minor=4, patch=5, prerelease='pre.2', build='build.4')\r\n```\r\n\r\n# Discussions and Possible Solutions\r\n\r\nTo implement a somewhat more advanced constructor/initializer, we have these options:\r\n\r\n1. Program it manually with `isinstance` and if...else constructs\r\n1. Use the [`typing.overload`](https://docs.python.org/3.6/library/typing.html#typing.overload) function (suggested by @tlaferriere)\r\n1. Use [`functools.singledispatch`](https://docs.python.org/3.6/library/functools.html#functools.singledispatch)\r\n\r\nHowever, all three comes at a cost or an issue:\r\n\r\n1. Maybe not impossible, but the code would look probably ugly.\r\n1. \"The `@overload` decorator is purely for type hints, you can only specify one function body and it has to distinguish the different types using isinstance.` (_Originally posted by @tlaferriere in https://github.com/python-semver/python-semver/issues/258#issuecomment-650648949_)\r\n1. Is not possible with an `__init__` method. The `singledispatch` works only for _functions_(!), *not* methods. For methods we would need [`functools.singledispatchmethod`](https://docs.python.org/3.8/library/functools.html#functools.singledispatchmethod) which is only available from Python \u003e= 3.8.\r\n\r\n----\r\n\r\nAnother idea goes into a completely different direction. Maybe we shouldn't change the `Version` class much, but offer a much shorter variant: `semver.v`.\r\n\r\n```python\r\nfrom functools import singledispatch\r\n\r\n# ...\r\n@singledispatch\r\ndef ver(major, minor=0, patch=0, prerelease=None, build=None) -\u003e \"Version\":\r\n    return Version(major, minor, patch, prerelease, build)\r\n    \r\n@ver.register(bytes)\r\n@ver.register(str)\r\ndef _(ver: str) -\u003e \"Version\":\r\n    if isinstance(ver, bytes):\r\n       ver = str(ver, \"utf-8\")\r\n    if \".\" in ver:\r\n        return Version.parse(ver)\r\n    return Version(int(ver))\r\n\r\n@ver.register(Version)\r\ndef _(ver: \"Version\") -\u003e \"Version\":\r\n    return ver\r\n```\r\n\r\nWhich means, we could just use `semver.v` as a much shorter variant:\r\n\r\n```python\r\n\u003e\u003e\u003e import semver\r\n\u003e\u003e\u003e semver.v(\"1.2.3\")\r\nVersion(major=1, minor=2, patch=3, prerelease=None, build=None)\r\n```\r\n\r\nOne drawback could be that `v` is quite short. Maybe too short? Especially if you import it with `from semver import v` it could be easily overwritten by other, local variables.\r\nThat could be a bit avoided to use capital `V` or `ver`. Or we use the much longer name `semver.version`.\r\n\r\nThoughts? Any other ideas? Would that be worth the effort?\r\n\r\n@tlaferriere @gsakkis @ppkt ","author":{"url":"https://github.com/tomschr","@type":"Person","name":"tomschr"},"datePublished":"2020-10-26T19:22:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/303/python-semver/issues/303"}