Question

I’m at the moment trying to make a very simple app that will greet depending on the time of the day. My code is:

open System

let read() = Console.Read() 
let readLine() = Console.ReadLine()

let clockMsg min max todo = 
    if (DateTime.Now.Hour > min) && (DateTime.Now.Hour < max) then todo

let name = readLine()

clockMsg 0 8 <| printfn "Go to bed, %s!" name
clockMsg 8 12 <| printfn "Good morning, %s!" name
clockMsg 12 18 <| printfn "Good afternoon, %s!" name

read() |> ignore

Now is my question, how can only ONE of the function calls be valid, but all three will no matter what, print their messages?

Answer 1

Agree with BrokenGlass. What you probably want to do is:

clockMsg 0 8 (fun() -> printfn "Go to bed, %s!" name)

and this change in clockMsg:

let clockMsg min max todo = 
    if (DateTime.Now.Hour > min) && (DateTime.Now.Hour < max) then todo()