Chris's Wiki :: blog/python/TypeHintsProbablyWorthItForMe

I recently added type hints to a little program, and that experience wasn't entirely positive that left me feeling that maybe I shouldn't bother. Because I don't promise to be consistent, I went back and re-added type hints to the program all over again, starting from the non-hinted version. This time I did the type hints rather differently and the result came out well enough that I'm going to keep it.

Perhaps my biggest change was to entirely abandon NewType(). Instead I set up two NamedTuples and used type aliases for everything else, which amounts to three type aliases in total. Since I was using type aliases anyway, I only added them when it was annoying to enter the real type (and I was doing it often enough). I skipped doing a type alias for 'list[namedTupleType]' because I couldn't come up with a name that I liked well enough and that it's a list is fundamental to how it's interacted with in the code involved, so I didn't feel like obscuring that.

Adding type hints 'for real' had the positive aspect of encouraging me to write a bunch of comments about what things were and how they worked, which will undoubtedly help future me when I want to change something in six months. Since I was using NamedTuples, I changed to accessing the elements of the tuples through the names instead of the indexes, which improved the code. I had to give up 'list(adict.items())' in favour of a list comprehension that explicitly created the named tuple, but this is probably a good thing for the overall code quality.

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