I have a large program that changes the value of a variable, say `Var`, incrementing or decrementing. At any time when `Var = 5` I want to execute a subroutine, say `Flag()`.

What is the "appropriate" way to implement this?

What I have in mind is this:

```
While True
    If Var = 5 then
        Flag()
    End If
End While

```

But it looked quite silly.