Type mmaybe
    As Integer value
End Type

Function Bindf(m As mmaybe, f As Function(As mmaybe) As mmaybe) As mmaybe
    Return f(m)
End Function

Function Unit(i As Integer) As mmaybe
    Dim As mmaybe m
    m.value = i
    Return m
End Function

Function Decrement(mm As mmaybe) As mmaybe
    Dim As mmaybe result
    result.value = Iif(mm.value = 0, 0, mm.value - 1)
    Return Unit(result.value)
End Function

Function Triple(mm As mmaybe) As mmaybe
    Dim As mmaybe result
    result.value = Iif(mm.value = 0, 0, 3 * mm.value)
    Return Unit(result.value)
End Function

Dim As Integer values(3) = {3, 4, 0, 5}
Dim As Function(As mmaybe) As mmaybe Ptr decrementPtr = @Decrement
Dim As Function(As mmaybe) As mmaybe Ptr triplePtr = @Triple

For i As Integer = Lbound(values) To Ubound(values)
    Dim As mmaybe m1 = Unit(values(i))
    Dim As mmaybe m2 = Bindf(Bindf(m1, decrementPtr), triplePtr)
    Dim As String s1 = Iif(m1.value = 0, "none", Str(m1.value))
    Dim As String s2 = Iif(m2.value = 0, "none", Str(m2.value))
    Print Using "\  \ -> \  \"; s1; s2
Next i

Sleep