reader option functor

gistfile1.fsx

let howIsMyName t f = f >> Option.map t 


//mapReaderT :: (m a -> n b) -> ReaderT r m a -> ReaderT r n b

type Reader<'environment,'a> = 'environment -> 'a

//func application
let run environment (action : Reader<_,_>) = action environment

//functor
let map f (action : Reader<_,_>) : Reader<_,_> = action >> f

type OptionReader<'environment,'a> = Reader<'environment,'a option>
//('a -> 'b) -> ('environment -> 'a option) ('environment -> 'b option)
let mapOptionReader f (action : OptionReader<_,_>) : OptionReader<_,_> = action >> Option.map f 


let composeFmaps = (>>)
//('a -> 'b) -> ('environment -> 'a option) ('environment -> 'b option)
let mapOptionReaderC f = composeFmaps Option.map map f