What would we do without NULL?

Question

I once read that having nullable types is an absolute evil. I believe it was in an article written by the very person who created them(in Ada?) I believe this is the article

Answer 1

We'd create all kinds of strange constructs to convey the message of an object 'being invalid' or 'not being there', as seen in the other answers. A message that null can convey very well.

• The Null Object pattern has its disadvantages, as I explained here.
• Domain-specific nulls. This forces you to check for magic numbers, which is bad.
• Collection wrappers, where an empty collection means 'no value'. Nullable wrappers would be better, but that doesn't differ much from checking for null or using the Null Object pattern.

Personally, I would write some C# preprocessor that allows me to use null. This would then map to some dynamic object, which throws a NullReferenceException whenever a method is invoked on it.

Back in 1965, null references may have looked like a mistake. But nowadays, with all kinds of code analysis tools that warn us about null references, we don't have to worry that much. From a programming perspective null is a very valuable keyword.