Phpstan deals well with type definitions, arrays are powerful enough to contain whatever needed, and functions can be stored and passed around easily enough.

One of the best things with PHP is PsySH, or "Tinker" as the laravelists call it. It's not a REPL in the Common Lisp sense, but it is quite nice for an interactive programming shell. I've spent countless hours solving problems very, very quickly in it, and alongside Picolisp pil + and Elixir iex it's one of the earliest tools I install on a new system.

https://psysh.org/

The thing I miss the most is a nice concurrency story. It has become better but it's still a bit of a mess, often it's nicest to just implement workers as PHP and then implement control somewhere else, e.g. Elixir, or grab one of the application servers that are nowadays a thing in PHP.

If you're accessing an uninitialized property or checking if a property is uninitialized, you're probably already doing something wrong.

The point of class properties with no default value is that you're supposed to set them either in the constructor, immediately after creating an instance, or via some other method that guarantees they'll have a value by the time you need to read them (such as deserialization with validation).

If you want your properties to have a default "unset" value that you can trivially check for, that's what null is for. The author doesn't make it clear whether they are aware that you can declare a nullable string and give it the default value of null, but I hope they are.

Surprisingly enough, I was more productive in PHP than I was in perl. Perhaps perl is even stranger than PHP.