Programming Principles: Optionals Vs Null Or Undefined ( www.tiny.cloud )

dneaves , 11 months ago

After some slight frustration with the “Monadic” (Haskell/Elm) approach to null when learning Elm, I actually fully embrace it now:

<span style="color:#323232;">unNullString : Maybe String -> String
</span><span style="color:#323232;">unNullString nullable = 
</span><span style="color:#323232;">    case nullable of
</span><span style="color:#323232;">        Just str ->
</span><span style="color:#323232;">            str
</span><span style="color:#323232;">        Nothing ->
</span><span style="color:#323232;">            ""
</span>

• A) Now I try to avoid nullables when possible, because handling it everywhere is often more annoying than just expecting the type (even in non-monadic languages like Python)
• B) This is theoretically a better practice anyway. Why have a nullable string when you can just have an empty string? Or a nullable array/list/object/dict/etc when you can just have an empty one? Why have a nullable quantity of items when you can just have 0? If you really, really think you need a nullable bool, you don’t: just make a data (Haskell)/type (Elm)/enum (others) at this point. Most other things could just become an data/type/enum as well.

We null things for no reason, too often. Usually laziness.