I was watching a video with Kent Beck speaking somewhere, I’m not sure which one because there were like 3 different videos. But he was categorizing coders into “lumpers” and “splitters”. I apparently am a “splitter” because I’m splitting up my functions like crazy. If I were a “lumper” I would write larger functions. Honestly, I’m not sure which he is or if he prefers people to be one or the other, but there it is. My name is Jon and I’m a “splitter”.

Hence why I don’t like this big code block full of If/ElseIf combos:

Private Function FieldChanged(Field As Access.Control) As Boolean
    Dim retVal As Boolean
    If OnlyOneFieldIsNull(Field.OldValue, Field.Value) Then
        retVal = True
    ElseIf IsNull(Field.OldValue) And IsNull(Field.Value) Then
        retVal = False
    Else
        If Field.OldValue <> Field.Value Then
            retVal = True
        End If
    End If
    FieldChanged = retVal
End Function

Ok, so today I’m moving on to refactor this. I’m about to create a new function I think. Yeah, started to create a second new function then stopped, it wasn’t needed. Here’s what I got now for the whole set of null/not null checks for whether the field changed:

Private Function FieldChanged(Field As Access.Control) As Boolean
    Dim retVal As Boolean: retVal = False
    If AnyFieldIsNull(Field.OldValue, Field.Value) Then
        retVal = OnlyOneFieldIsNull(Field.OldValue, Field.Value)
    Else
        retVal = (Field.OldValue <> Field.Value)
    End If
    FieldChanged = retVal
End Function

Private Function AnyFieldIsNull(OldValue As Variant, NewValue As Variant) As Boolean
    AnyFieldIsNull = IsNull(OldValue) Or IsNull(NewValue)
End Function

Private Function OnlyOneFieldIsNull(OldValue As Variant, NewValue As Variant) As Boolean
    OnlyOneFieldIsNull = OldIsNullNewIsNot(OldValue, NewValue) Or OldIsNotNullNewIs(OldValue, NewValue)
End Function

Private Function OldIsNullNewIsNot(OldValue As Variant, NewValue As Variant) As Boolean
    OldIsNullNewIsNot = IsNull(OldValue) And Not IsNull(NewValue)
End Function

Private Function OldIsNotNullNewIs(OldValue As Variant, NewValue As Variant) As Boolean
    OldIsNotNullNewIs = Not IsNull(OldValue) And IsNull(NewValue)
End Function

At this point I’ve reduced it down to 1 If/Else and I feel at least a little better about it even if it’s not perfect. Ok, and the tests all still pass. So what’s next? As I’ve been gleaning info from various sources on Test Driven Development, I’ve discovered that Kent Beck, a long time TDD proponent who in his own terms “re-discovered” it for my generation, makes lists of changes and then writes tests according to those lists.

So far, I’ve just sort of gone of the cuff and tried to make the tests as I go along, like, what do I want to do next? I told you guys I’m just a beginner at this and trying to learn it, right? So how about a list of the tests I might want for this auditor as we move forward? I’ll revisit my initial design thoughts and then see if I can make a list of things I want this Form Auditor to do.

Ah, my tomato timer just went off, so that will be the next writing assignment for me.