If I have a function that attempts to divide a starting number two times. The entire workflow has to return a boolean.
let divideBy bottom top =
if bottom = 0 then None
else Some (top/bottom)
let divideByWorkflow init x y =
match init |> divideBy x with
| None -> false
| Some a ->
match a |> divideBy y with
| None -> false
| Some b -> true
let good = divideByWorkflow 12 3 2
let bad = divideByWorkflow 12 3 0
Is the following builder correct?
type BoolMaybe = BoolMaybe with
member __.Bind (expr, f) =
match expr with
| Some value -> f value
| None -> false
member __.Return expr = expr
let divideByWorkflow init x y =
BoolMaybe {
let! a = init |> divideBy x
let! b = a |> divideBy y
return true
}
I concur with Dzoukr's answer, mine looks just slightly different:
let divideBy bot top =
match bot with
| 0 -> None
| _ -> Some (top / bot)
let divideByWorkflow init x y =
Some init
|> Option.bind (divBy x)
|> Option.bind (divBy y)
|> Option.isSome
No computation expression required, it does not seem to add any benefits here.