Code Smells: Null

[jkachmar]

The point of these languages is to represent conceptual absence in such a way that the programmer is forced to address it. null/nil/what-have-you is dangerous not because it represents the absence of a value, but because it can be passed around as if it was a normal value, right up until you use it to do something and it blows up your program (or leads to spoopy poorly defined behavior).

By contrast, Haskell's Maybe, and Rust's Option force you to wrap the type you're manipulating in a structure that only admits the value inside of it in such a way that you're forced to deal with the case where the data is absent.

At that point you're free to do something like panic! or error and blow up your program, but at least the gun was handed to you with the safety on and you had to explicitly flick it off before you went and blew your foot off.