Elm has the option to output errors as JSON (via a flag), and something like that is handy for writing tooling around it. I'm trying to integrate pytype into ALE and this would make it a lot easier.

We get the return annotation for free, so we should allow users to do something with it.

Hi,
Will it be possible to add support for optional configuration files, the same general idea as ConfigArgParse: https://github.com/bw2/ConfigArgParse

The idea is to be able to pass a file path as an argument and some additional arguments.
the logic should be to first parse the config file and then parse the rest of the arguments.
Thank you!