Trivial writer example

TrivialWriterExample.fs

type Log = string * int

let f: Writer<Log, bool> =
  writer {
    let x = 1
    do! write ("x", x)
    let y = 2
    do! write ("y", y)
    let z = x + y
    do! write ("result", z)
    return z > 0
  }

let (result: bool, logs: Log list) = run f

printfn "%A" result
printfn "%A" logs