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it's a comment which can trigger an action (if you run mypy). So, unlike a comment, which does nothing, if you run mypy and get some warnings, you can then do

by xarope 5y ago

it's a comment which can trigger an action (if you run mypy). So, unlike a comment, which does nothing, if you run mypy and get some warnings, you can then do something about it (whether it's just # type: ignore or you realise you made a mistake with allocating to variable new_value versus newvalue/new_valu/etc) (btw, in case someone objects, some comments DO do something, e.g. golang's godoc examples)

the_af 5y ago
Now I'm confused because the root comment I was replying to asserted that type hints are for documenting, not for checking. If they are for checking, then my other opinion stands: that they are not very good at it (compared to my experience with statically typed languages, even with Typescript!).
- dragonwriter 5y ago
  They are for documenting and checking. Obviously, if static typing is your only concern, you wouldn't have picked Python to start with, but if you did have a reason to pick Python, you can get a large subset of the value of static typing for correctness and dev-tine information via Python’s support for type hints and the typecheckers (mypy keeps getting pointed to, but it's not the only one) that support it.
  - the_af 5y ago
    Yes, obviously. There are outside factors why Python was chosen. I tend to work with whatever language is needed, and try to make the best of it. I've tried mypy and pytype, and found both to be unsatisfying and hard to sell to the team (which as I mentioned, don't even like writing tests). If you're thinking "well, that's a culture/professionalism rather than a technical problem", you are absolutely right! But I'm left wondering if a language that was better at static typing would be better because, a- the checking would be mandatory, and b- it would be demonstrably more effective than Python's "optional" checking/hinting. At least it'd remove one variable from the problem. Or maybe not, who knows.

by xarope 5y ago

the_af 5y ago

Now I'm confused because the root comment I was replying to asserted that type hints are for documenting, not for checking. If they are for checking, then my other opinion stands: that they are not very good at it (compared to my experience with statically typed languages, even with Typescript!).

dragonwriter 5y ago
They are for documenting and checking. Obviously, if static typing is your only concern, you wouldn't have picked Python to start with, but if you did have a reason to pick Python, you can get a large subset of the value of static typing for correctness and dev-tine information via Python’s support for type hints and the typecheckers (mypy keeps getting pointed to, but it's not the only one) that support it.
- the_af 5y ago
  Yes, obviously. There are outside factors why Python was chosen. I tend to work with whatever language is needed, and try to make the best of it. I've tried mypy and pytype, and found both to be unsatisfying and hard to sell to the team (which as I mentioned, don't even like writing tests). If you're thinking "well, that's a culture/professionalism rather than a technical problem", you are absolutely right! But I'm left wondering if a language that was better at static typing would be better because, a- the checking would be mandatory, and b- it would be demonstrably more effective than Python's "optional" checking/hinting. At least it'd remove one variable from the problem. Or maybe not, who knows.