SuccessOrFailure.fs

[<AutoOpen>]
module SuccessOrFailure =
    type SuccessOrFailure<'a>  = 
    | Success of 'a
    | Failure of exn
    
    let point v = Success v

    let (>>=) m f =
        match m with
        | Success x -> 
            try 
                f x
            with ex -> Failure ex
        | Failure x -> Failure x
          
    let (<!>) m f =
        m >>= (fun x -> f x |> Success)

    let extract = function
    | Success x -> x
    | Failure x -> raise x

    type SuccessOrFailureBuilder () =
        member this.Bind (m, f) = m >>= f
        member this.Return v = point v
        member this.Yield v = point v
        member this.ReturnFrom m = m
        member this.YieldFrom m = m
        member this.Fail v = Failure v
        member this.Zero() = 
            Success

    let succeed = new SuccessOrFailureBuilder ()
            
    let foldrM f z = List.fold (fun m a -> m >>= f a) (point z)