Computation Expression

Option Computation Expression

Namespace: FsToolkit.ErrorHandling

Examples:

Example 1

// Option<int>
let addResult = option {
  let! x = tryParseInt "35"
  let! y = tryParseInt "5"
  let! z = tryParseInt "2"
  return add x y z
}

Example 2

Example taken from here

// int -> int -> int option
let tryDivide x y =
    match y with
    | 0 -> None
    | _ -> Some (x / y)

// int -> int -> int option
let multiplyIfEven x y =
    match y % 2 with
    | 0 -> Some <| x * y
    | _ -> None
 
// int option  
let resultNone = option {        
    let! result = tryDivide 5 3
    let mapped = result * 5
    return! multiplyIfEven 5 mapped
}
// result: None

// int option  
let resultSome = option {        
    let! result = tryDivide 6 3
    let mapped = result * 5
    return! multiplyIfEven 5 mapped
}
// result: Some 50