Question

I have a set of five functions, that could be called one of five ways. I’m expressing that with patern-matching like so,

type Configure = ReaderT Config IO ()
data Step = PreVal
          | PreProc
          | Proc
          | PostProc
          | PostVal

foo :: Step -> Configure
foo PreVal = do some stuff
foo PreProc = do some stuff

and so on bar and baz are set up similarly

I know how to use sequence to call a list of actions. Given a [Step], how could I go about calling [foo,bar,baz]. in sequence, while also calling each possible step.

so it should do this
foo PreVal
foo PreProc
… and so on
bar Preval
bar PreProc
.. and so on
baz …

Answer 1

mapM_ (\ f -> mapM_ f [PreVal, PreProc, Proc, PostProc, PostVal]) [foo, bar, baz]