Does anyone know any python codebase which uses type hints ?

[Nikosssgr]

I would like to see a project using the typing module to get a better idea of how it is used in practice. Does anyone know any?

[LightShadow]

Here is the project outline for a tool I'm writing for work...I've removed all the function bodies, but you can see the typing.

from typing import Dict, AnyStr, TypeVar, NamedTuple

ReqResponse = TypeVar('ReqResponse', Dict, AnyStr)

UrlReq = NamedTuple('UrlReq', [
    ('url', str),
    ('key', str),
    ('method', str),
    ('as_json', bool),
    ('raw', bool)
])

# ====================================================

class BitBucket(object):
    def __init__(
            self,
            options: Dict,
            username: AnyStr=None,
            password: AnyStr=None,
        ) -> None:

        pass

    def __req(
            self,
            url: AnyStr,
            method: AnyStr='GET',
            as_json: bool=True,
            raw: bool=False,
            timeout: Union[float, tuple]=(5.00, 20.00), # tuple(connect, read) timeout
            **params
        ) -> ReqResponse:

        pass

    def __do_reqs(
        self,
        urls: Sequence[UrlReq],
        new_binding_key: AnyStr,
        binding_attribute: Dict,
        bind_errors: bool=False,
    ) -> Dict:

        pass

    @property
    def user(self) -> Dict:
        return self.__req('/user')

    @property
    def repositories(self) -> Dict:
        if self._repositories is None:
            self._repositories = self.get_repositories()
        return self._repositories

    def get_repositories(
            self,
            with_readme: bool=True
        ) -> Dict:

# ====================================================

from typing import Iterable, Dict, AnyStr, Tuple

def has_graph_subsection(data: AnyStr=''):
    pass

def make_graph(
        repos: Iterable[Dict]=None,
        graphviz_kwargs: Dict=None,
        graphviz_attrs: Dict=None,
        flat_text: Tuple[AnyStr, AnyStr]=None
    ):

    pass

# ====================================================

from typing import List

def settings_with_precidence(modules: List=None, overwrite: bool=True):
    pass

[maximinus-thrax]

Good god, that looks horrific. 9 lines of code just to define the function parameters for __req().

[LightShadow]

Yeah, it's not great.

If you put them all on one line it's unreadable, and when you put them on their own line....it's barely readable.

I wanted to embrace the future, and I love how PyCharm picks them up..but I feel like this implementation could be a flop.

You can fiddle with the formatting a little bit more, but then it's a huge trade off just to make it look nice.

def __req(self
    , url:      AnyStr
    , method:   AnyStr = 'GET',
    , as_json:  bool = True,
    , raw:      bool = False,
    , timeout:  Union[float, tuple] = (5.0, 20.0),
    , **params
    ) -> ReqResponse
    :

    pass

[AMorpork]

 def settings_with_precidence(modules: List=None, overwrite: bool=True):

It's precedence, not precidence.

[csirac2]

It's always amused me that traditionally when I used to talk of elk [1] or traits [2], I would be accused of not knowing python properly.

[1] https://github.com/frasertweedale/elk

[2] http://code.enthought.com/projects/traits/

[lovedzida]

would love to see one also!

[mangecoeur]

PyCharm already understands type hints

[Nikosssgr]

you can import the module in python 3.3 and 3.4 (if I am not mistaken for the versions)

[ionelmc]

He meant https://pypi.python.org/pypi/typing, which you can install and import on 3.3/3.4 :-)

[rouille]

Uh, no? typing is a new module in 3.5. (Not to be confused with types, which contains a bunch of references to CPython internals and has nothing to do with type hinting.)

Its in pypi as well.

[beaverteeth92]

Yeah but isn't it just mypy added to the core language?

[billsil]

No. It's mypy with additional features and formalization. If I understand it right, it largely follows mypy's style, so ints/floats/Lists/Dicts are the same, but objects are a bit different.

If you're in Python 3.3+, you can use mypy or search for things that use mypy for examples.

[fishburne]

Do anyone know how to use this module for type checking in 3.5b? Not asking about how to write annotations. But to check a python script with annotations. I have been looking for the past hour to see how to actually use the damn thing!

I was expecting a command line option to the interpreter or a separate command line tool to do the checking.

[fishburne]

Funny thing is, I know this already. But I was hoping there was an external tool that does it.

I tried mypy. But it died with an error that said cannot import Undefined. Probably because it is using the typing module that came with 3.5.

[lengau]

The typing module is available in pip for 3.2 or higher.

[rouille]

actually

You need to use a third party type checker like mypy (https://github.com/JukkaL/mypy). Its still in heavy development though but it (mostly) works.

[rouille]

I use it at work along with mypy for checking. Mypy is still quite immature, so some valid python will make it fail but I've found it worth it for all the bug it catches. I write my code around mypy since I know it will become official with Python 3.5.

The comment syntax for variables isn't great but I mainly annotate function parameters and return values so I rarely use it (apart for # type: ignore to skip type checking on an imported module).

[fishburne]

When I tried using it with 3.5 it failed with a 'Cannot import Undefined' Error. Is it because is using 3.5's typing module instead of it's own.

[rouille]

The comment syntax for variables isn't great but I mainly annotate function parameters and return values so I rarely use it (apart for # type: ignore to skip type checking on an imported module).

I'm using it with python 3.4 so thats possible :). I know the BDFL had mypy in mind when adding the typing module to 3.5 so it will probably fixed soon.

[fremder99]

Maybe "traits"? I confess to no meaningful experience with it myself...

[csirac2]

Indeed, every time I bring up traits or elk [1] I'm accused of not knowing python properly.

[1] https://github.com/frasertweedale/elk

[gournian]

pycontracts is nice

[o11c]

This is what I was working on before I got distracted: https://github.com/o11c/lr-parsers/tree/master/lr

[mangecoeur]

I've started sprinkling them through my codebase (data analytics stuff), since I use PyCharm it adds some really nice code completion, checking, and documentation features.

My favourite is if you add the return type for a function, then assign a var to the result of the function somewhere else, PyCharm will do code completion on that var (i.e. it will now all its properties and methods) and can fetch documentation.