dialyxir

Also I found Dialyzer (success typing checker) to be helpful in large projects: http://learnyousomeerlang.com/dialyzer The way success typing works it is a bit like static typing but when it cannot deduce the types it assumes success. However when it finds a discrepancy it is always right. So the more type annotations you add, and the more precise they are the more benefits you get from it. It has also been there for many years. I think Python only very recently has started getting the same kind of things via MyPy. Of course, they had to call it something differently (Optional Static Typing). Elixir has a wrapper around it, it seems: https://github.com/jeremyjh/dialyxir but never used it (I user Erlang mostly).

Elixir and Erlang both actually have static typing in the style of Facebook's Flow - type annotations can be added to your functions[0] and there's a tool, Dialyzer[1], which can be run via Mix[2] to type-check your programs. It's not perfect - among other things, it can't type-check certain things that can and do happen in Erlang/Elixir programs, and won't complain about some errors - but it's better than being purely dynamic at not a whole lot more effort. [0] http://elixir-lang.org/getting-started/typespecs-and-behavio... [1] http://erlang.org/doc/apps/dialyzer/dialyzer_chapter.html [2] https://github.com/jeremyjh/dialyxir