No mocking needed for unit testing, command query separation. Do you still use some DI in impure functions; partial applications, Mark is not a fan of DI containers and doesn't know of any for F#. Are partial functions functional, Haskell keeps its impure functions at the edge, "impure-pure-impure sandwich" sandwich - the origin of the word "sandwich", an example of a translator application, don't lose sight of the other tenets of programming, upcoming conferences.