these things are harder to implement with functional programming languages. OOP languages have the benefit of having all the classes, methods, fields, and properties known ahead of time.
In functional programming you’ll say something like:
valid_values = filter (x: x.is_valid) all_values;
It’s hard to know what you were meaning to type. Some languages have “type holes”, but generally you still need to write the majority of the expression, and leave only one “hole” open. Unfortunately, nix doesn’t have this as it’s dynamically typed.
But in general, I agree, I had to “cut my teeth” by looking at other code within nixpkgs. And the IDE experience isn’t great. I just use vim + coc + vim-nix. But, I generally have to know ahead of time, the code I need to write.
In defense of functional programming, it takes me a bit longer to get started because I have to learn the “prelude” of functions that are commonly used. The most common functions (map, fold, filter, etc) usually carry over between languages, so if you’re familiar with another functional programming language, then learning this is pretty quick.
(rant warning)
Another benefit of functional programming is that I don’t usually experience, “I need to do X, and class Y looks like the right class. Let me learn how this one class is defined, and it’s very similar to this other class Z; but since it needs to differ in this one regard, it should be it’s own class. Oh, and since class Z was sealed, this makes sense why they didn’t make class Y a subclass of Z; but now it uses slightly different conventions so it’s similar but not the same now. Oh, and I forgot that this class’s parent-parent-parent-class already implements this, and I should have just done that.”
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