# Plugin for mypy to support zope.interface
[](https://travis-ci.org/Shoobx/mypy-zope)
[](https://coveralls.io/github/Shoobx/mypy-zope)
[](http://mypy-lang.org/)
The goal is to be able to make zope interfaces to be treated as types in mypy
sense.
## Usage
Install both mypy and mypy-zope:
```sh
pip install mypy-zope
```
Edit `mypy.ini` file in your project to enable the plugin:
```ini
[mypy]
namespace_packages=True
plugins=mypy_zope:plugin
```
You're done! You can now check your project with mypy:
```sh
mypy your-project-dir
```
## What is supported?
You can browse
[sample files](https://github.com/Shoobx/mypy-zope/tree/master/tests/samples)
to get some sense on what features are supported and how they are handled.
### Interface declarations
You can define the interface and provide implementation:
```python
class IAnimal(zope.interface.Interface):
def say() -> None:
pass
@zope.interface.implementer(IAnimal)
class Cow(object):
def say(self) -> None:
print("Moooo")
animal: IAnimal = Cow()
animal.say()
```
The interface `IAnimal` will be treated as superclass of the implementation
`Cow`: you will be able to pass an implementation to functions accepting an
interface and all the usual polymorphism tricks.
It is also possible to declare the implementation using `classImplements`
function with the same effect as `@imlementer` decorator. This is useful if
you do not control the code that defines the implementation class.
```python
classImplements(Cow, IAnimal)
animal: IAnimal = Cow()
```
### Schema field type inference
A limited support for defining attributes as `zope.schema.Field`s is supported too:
```python
class IAnimal(zope.interface.Interface):
number_of_legs = zope.schema.Int(title="Number of legs")
@zope.interface.implementer(IAnimal)
class Cow(object):
number_of_legs = 4
```
In context of an interface, some known `zope.schema` field types are
automatically translated to python types, so the `number_of_legs` attributes is
getting the type `int` in the example above. That means mypy will report an
error if you try to assign string to that attribute on an instance of `IAnimal`
type. Custom fields or fields not recognized by plugin are given type `Any`.
### Field properties
Support for `zope.schema.FieldProperty` is limited, because type information is
not transferred from an interface to implementation attribute, but mypy doesn't
report errors on sources like this:
```python
class IAnimal(zope.interface.Interface):
number_of_legs = zope.schema.Int(title="Number of legs")
@zope.interface.implementer(IAnimal)
class Cow(object):
number_of_legs = zope.schema.FieldProperty(IAnimal['number_of_legs'])
```
The type of `Cow.number_of_legs` will become `Any` in this case, even though
`IAnimal.number_of_legs` would be inferred as `int`.
### Adaptation pattern
Zope interfaces can be "called" to lookup an adapter, like this:
```python
class IEUPowerSocket(zope.interface.Interface):
def fit():
pass
adapter = IEUPowerSocket(us_plug)
adapter.fit()
```
Type of the `adapter` variable will be set to `IEUPowerSocket`.
### Conditional type inference
When using `zope.interface`'s `implementedBy()` and `providedBy()` methods
in an if statement, `mypy` will know which type it is inside those statements.
```python
if IAnimal.providedBy(ob):
ob.number_of_legs += 2
```
### Declaration of overloaded methods in interfaces
Similarly to regular [overloaded
functions](https://docs.python.org/3/library/typing.html#typing.overload),
`@overload` declarations are supported in interfaces as well:
```python
class IAnimal(zope.interface.Interface):
@overload
def say() -> str:
...
@overload
def say(count: int) -> List[str]:
...
def say(count: int = None) -> Union[str, List[str]]:
pass
@zope.interface.implementer(IAnimal)
class Cow(object):
@overload
def say(self) -> str:
...
@overload
def say(self, count: int) -> List[str]:
...
def say(self, count: int = None) -> Union[str, List[str]]:
if count is None:
return "Mooo"
return ["Mooo"] * count
```
### Type stubs for zope.interface and zope.schema
`mypy-zope` ships with type stubs (`*.pyi` files) for `zope.interface` and
`zope.schema` packages. They are enabled automatically as soon as plugin is
enabled.
## What is not supported?
These `zope.interface` features are not supported:
* Declaring modules as interface implementers.
* Type inference for `zope.schema.List` and `zope.schema.Dict` fields.
* Stub files are largely incomplete
* Interface compatibility checker will not type-check non-method attributes
## Ready to use!
Currently, the project is used in production in various substantially large
projects and considered production-grade, however there still might be subtle
bugs around. Suggestions and pull requests are welcomed!
Raw data
{
"_id": null,
"home_page": "https://github.com/Shoobx/mypy-zope",
"name": "mypy-zope",
"maintainer": "",
"docs_url": null,
"requires_python": "",
"maintainer_email": "",
"keywords": "mypy,zope,interfaces,typing",
"author": "Andrey Lebedev",
"author_email": "andrey.lebedev@gmail.com",
"download_url": "https://files.pythonhosted.org/packages/84/51/8d38eac4249560fe0267017a9671c85b5be663a14eff4033a72db6de33ac/mypy-zope-1.0.4.tar.gz",
"platform": null,
"description": "# Plugin for mypy to support zope.interface\n\n[](https://travis-ci.org/Shoobx/mypy-zope)\n[](https://coveralls.io/github/Shoobx/mypy-zope)\n[](http://mypy-lang.org/)\n\nThe goal is to be able to make zope interfaces to be treated as types in mypy\nsense.\n\n## Usage\n\nInstall both mypy and mypy-zope:\n```sh\npip install mypy-zope\n```\n\nEdit `mypy.ini` file in your project to enable the plugin:\n\n```ini\n[mypy]\nnamespace_packages=True\nplugins=mypy_zope:plugin\n```\n\nYou're done! You can now check your project with mypy:\n\n```sh\nmypy your-project-dir\n```\n\n## What is supported?\n\nYou can browse\n[sample files](https://github.com/Shoobx/mypy-zope/tree/master/tests/samples)\nto get some sense on what features are supported and how they are handled.\n\n### Interface declarations\n\nYou can define the interface and provide implementation:\n\n```python\nclass IAnimal(zope.interface.Interface):\n def say() -> None:\n pass\n\n@zope.interface.implementer(IAnimal)\nclass Cow(object):\n def say(self) -> None:\n print(\"Moooo\")\n\nanimal: IAnimal = Cow()\nanimal.say()\n```\n\nThe interface `IAnimal` will be treated as superclass of the implementation\n`Cow`: you will be able to pass an implementation to functions accepting an\ninterface and all the usual polymorphism tricks.\n\nIt is also possible to declare the implementation using `classImplements`\nfunction with the same effect as `@imlementer` decorator. This is useful if\nyou do not control the code that defines the implementation class.\n\n```python\nclassImplements(Cow, IAnimal)\n\nanimal: IAnimal = Cow()\n```\n\n### Schema field type inference\nA limited support for defining attributes as `zope.schema.Field`s is supported too:\n\n```python\nclass IAnimal(zope.interface.Interface):\n number_of_legs = zope.schema.Int(title=\"Number of legs\")\n\n@zope.interface.implementer(IAnimal)\nclass Cow(object):\n number_of_legs = 4\n```\n\nIn context of an interface, some known `zope.schema` field types are\nautomatically translated to python types, so the `number_of_legs` attributes is\ngetting the type `int` in the example above. That means mypy will report an\nerror if you try to assign string to that attribute on an instance of `IAnimal`\ntype. Custom fields or fields not recognized by plugin are given type `Any`.\n\n### Field properties\n\nSupport for `zope.schema.FieldProperty` is limited, because type information is\nnot transferred from an interface to implementation attribute, but mypy doesn't\nreport errors on sources like this:\n\n```python\nclass IAnimal(zope.interface.Interface):\n number_of_legs = zope.schema.Int(title=\"Number of legs\")\n\n@zope.interface.implementer(IAnimal)\nclass Cow(object):\n number_of_legs = zope.schema.FieldProperty(IAnimal['number_of_legs'])\n```\n\nThe type of `Cow.number_of_legs` will become `Any` in this case, even though\n`IAnimal.number_of_legs` would be inferred as `int`.\n\n### Adaptation pattern\n\nZope interfaces can be \"called\" to lookup an adapter, like this:\n\n```python\nclass IEUPowerSocket(zope.interface.Interface):\n def fit():\n pass\n\nadapter = IEUPowerSocket(us_plug)\nadapter.fit()\n```\n\nType of the `adapter` variable will be set to `IEUPowerSocket`.\n\n### Conditional type inference\n\nWhen using `zope.interface`'s `implementedBy()` and `providedBy()` methods\nin an if statement, `mypy` will know which type it is inside those statements.\n\n```python\nif IAnimal.providedBy(ob):\n ob.number_of_legs += 2\n\n```\n\n### Declaration of overloaded methods in interfaces\n\nSimilarly to regular [overloaded\nfunctions](https://docs.python.org/3/library/typing.html#typing.overload),\n`@overload` declarations are supported in interfaces as well:\n\n```python\nclass IAnimal(zope.interface.Interface):\n @overload\n def say() -> str:\n ...\n\n @overload\n def say(count: int) -> List[str]:\n ...\n\n def say(count: int = None) -> Union[str, List[str]]:\n pass\n\n\n@zope.interface.implementer(IAnimal)\nclass Cow(object):\n @overload\n def say(self) -> str:\n ...\n\n @overload\n def say(self, count: int) -> List[str]:\n ...\n\n def say(self, count: int = None) -> Union[str, List[str]]:\n if count is None:\n return \"Mooo\"\n return [\"Mooo\"] * count\n```\n\n### Type stubs for zope.interface and zope.schema\n\n`mypy-zope` ships with type stubs (`*.pyi` files) for `zope.interface` and\n`zope.schema` packages. They are enabled automatically as soon as plugin is\nenabled.\n\n\n## What is not supported?\n\nThese `zope.interface` features are not supported:\n\n* Declaring modules as interface implementers.\n* Type inference for `zope.schema.List` and `zope.schema.Dict` fields.\n* Stub files are largely incomplete\n* Interface compatibility checker will not type-check non-method attributes\n\n## Ready to use!\n\nCurrently, the project is used in production in various substantially large\nprojects and considered production-grade, however there still might be subtle\nbugs around. Suggestions and pull requests are welcomed!\n\n",
"bugtrack_url": null,
"license": "",
"summary": "Plugin for mypy to support zope interfaces",
"version": "1.0.4",
"project_urls": {
"Homepage": "https://github.com/Shoobx/mypy-zope"
},
"split_keywords": [
"mypy",
"zope",
"interfaces",
"typing"
],
"urls": [
{
"comment_text": "",
"digests": {
"blake2b_256": "9dc9627b58b9c48b1459f31869f216326b36bd75cb0c5efc2febe6857ccaa0de",
"md5": "cca5a62edfefe964e7c27cdd57713f6f",
"sha256": "c7298f93963a84f2b145c2b5cc98709fc2a5be4adf54bfe23fa7fdd8fd19c975"
},
"downloads": -1,
"filename": "mypy_zope-1.0.4-py3-none-any.whl",
"has_sig": false,
"md5_digest": "cca5a62edfefe964e7c27cdd57713f6f",
"packagetype": "bdist_wheel",
"python_version": "py3",
"requires_python": null,
"size": 32403,
"upload_time": "2024-03-12T19:54:17",
"upload_time_iso_8601": "2024-03-12T19:54:17.295747Z",
"url": "https://files.pythonhosted.org/packages/9d/c9/627b58b9c48b1459f31869f216326b36bd75cb0c5efc2febe6857ccaa0de/mypy_zope-1.0.4-py3-none-any.whl",
"yanked": false,
"yanked_reason": null
},
{
"comment_text": "",
"digests": {
"blake2b_256": "84518d38eac4249560fe0267017a9671c85b5be663a14eff4033a72db6de33ac",
"md5": "c2e5f4d142b18b4ec59f6674a47a7fb9",
"sha256": "a9569e73ae85a65247787d98590fa6d4290e76f26aabe035d1c3e94a0b9ab6ee"
},
"downloads": -1,
"filename": "mypy-zope-1.0.4.tar.gz",
"has_sig": false,
"md5_digest": "c2e5f4d142b18b4ec59f6674a47a7fb9",
"packagetype": "sdist",
"python_version": "source",
"requires_python": null,
"size": 33879,
"upload_time": "2024-03-12T19:54:19",
"upload_time_iso_8601": "2024-03-12T19:54:19.546259Z",
"url": "https://files.pythonhosted.org/packages/84/51/8d38eac4249560fe0267017a9671c85b5be663a14eff4033a72db6de33ac/mypy-zope-1.0.4.tar.gz",
"yanked": false,
"yanked_reason": null
}
],
"upload_time": "2024-03-12 19:54:19",
"github": true,
"gitlab": false,
"bitbucket": false,
"codeberg": false,
"github_user": "Shoobx",
"github_project": "mypy-zope",
"travis_ci": false,
"coveralls": false,
"github_actions": true,
"tox": true,
"lcname": "mypy-zope"
}
JSON
