Hello, I am reaching you in order to obtain feedback on this RFC proposal.
I have been playing with PHP 7 for a project in the company that I am currently working for. One of the many drawbacks that I saw in PHP was the there were no types. With type hinting I had confindence again in PHP. With return type hinting a wasn't able to resist to try it. So here I am, making a whole new platform entirely in PHP 7, using type hints in everything. Arguments and returns alike. Given my tendency to language purity imagine my surprise when my code inadvertently tryied to sneak a NULL into a method expecting an object... And failing thanks to strictness in object and null treatments in the new PHP 7. "SWEET!" I yelled. Now imagine my dumbfoundedness when a Repository of mine tryed to return a NULL, and because it ought to return have returned a User, it threw a TypeError. At first I said "sweet." But then I realized the problem. There are many times where we need uncertainty. Code is a reflection of reality, and as such, it must reflect uncertainty. NULL is a good enough way to express nonexistence, albeit a bad one. We have been using it in code for years, but it is also used to say many things. Things that cause uncertainty in the code. I receive a null, does it mean it doesn't exists? That it will exist? Should I allow it? Is it a good value? I for sure don't know. And in my experience, I have used it for many of those cases. And in many situations that I'm not proud of, all of them at the same time. So I want to "return a NULL". I want to express uncertainty, a nonexistence. But I want to express that I will return something. And I want to have this NULL checking at interpretation time. I want everything, and none of the drawbacks. As we say here in Argentina, I want the bread and the cake. What can we do to have it? After a bit of thought the Maybe monad came to me. My experience in Haskell reminded me of this. To have a structure than represents uncertainty, is the best way to take away the responsibility from NULL. To express it in no other way. But my experience in Java has taught me that Optional of something is not a good way to tackle the problem. I still have to check if my Optional isEmpty. I still have to check for null. That is because Java has that type erasure after compilation time that doesn't allow me to play nice with polymorphism. But maybe PHP can. Maybe PHP will give me the polymorphism at execution time to discern an empty Maybe from the one that is not. So I don't have to check for null ever again in my life. So my code can be free of nulls. So I can express uncertainty and nonexistance, while I return a User from my repository. I hope someone would like this idea. I'm also open to suggestions. Kind regards Facundo Martínez
