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by gameswithgo 2783 days ago
It doesn't seem like you are familiar with how option types get rid of null. You don't have to make up data to satisfy things not being null. You set them none, and the language either forces, or encourages usually, you to always check if the option is none or some.
1 comments

I use Option in Java quite a bit because I'm real sick of NPEs and cascading null checks in all-or-nothing flows. I would have preferred Java starting with something like Kotlin's approach where T is T not T|nil. You and the sibling might be missing the point of the post I linked, I think. It can be convenient to have formal assistance via e.g. the type checker that a function taking a non-null String returns a non-null Person with a non-null FirstName and LastName. But in the zeal to be rid of null to make programmers' lives a bit easier, when faced with a name that doesn't compose into 2 parts, someone has to decide what to do about that and who needs to care down the line. You can make up data ("FNU" as in the blog), set a convention (empty string), throw an exception, or declare either the whole Person structure Optional or at least certain fields. If you use a dynamic late-binding language you may have other options. Whatever you do, it ought to be consistent or robustly handled where the references interact with your DB, your processing programs, and your data displays. Finally when these references escape your system, as lots of real world data does, they necessarily escape any static criteria you once had on them, thus it's important to consider those third party systems have to live with your choice. Null is a convenient choice, not something to be villified so casually.