Add type annotations to c_source.py

[zariiii9003]

• add type annotations to c_source.py
• use float literals if --use-float is set
• do not cast double to float

Closes #604

[coveralls]

Pull Request Test Coverage Report for Build 7398162148

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.05%) to 93.535%

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Totals
Change from base Build 7359660138:	-0.05%
Covered Lines:	7249
Relevant Lines:	7750

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💛 - Coveralls

[andlaus]

looks good

[andlaus]

why the as {Foo}?

[zariiii9003]

I checked csource.py with mypy --strict and it complained about that file. These names are exported according to PEP 484:

Modules and variables imported into the stub are not considered exported from the stub unless the import uses the import ... as ... form or the equivalent from ... import ... as ... form. (UPDATE: To clarify, the intention here is that only names imported using the form X as X will be exported, i.e. the name before and after as must be the same.)

Alternatively, we could put them in __all__ if you like.

[andlaus]

Ok. I just think that this is a quite clumsy construct. does mypy complain without --strict?

[zariiii9003]

I replaced it with __all__. That works too.

[zariiii9003]

Now i removed __all__, because it causes issues with these star imports:

# Remove once less users are using the old package structure.
from .can import *  # noqa: F403