Comment by usgroup
12 days ago
In my opinion, if you are after the mystical experience of understanding functional programming, you're better off learning Prolog. I think it has more to offer in terms of insight, because wrapping your head around the language only takes a couple days, but wrapping your head around its consequences is a gift which keeps on giving for quite some time.
Immutable functional programming is basically what 80% of your Prolog code will look like. The benefit is that you'll be able to understand how everything works from end-to-end.
Prolog is a logic programming language though, I wouldn't expect it to have a lot of overlap with functional programming?
Prolog variables are immutable by default. Data structures are the same as the immutable functional programming counterparts (no arrays, and tree based everything). Recursion is the only way to loop. Map, filter, fold(l/r), reduce, accumulate, etc, are staple predicates.
As I said, 80% of your code, or more, will look just like a functional programme.
An execution pipeline in a functional language is just half a relation in Prolog. Prolog allows you to also run it 'backwards', you can provide the output and have it figure out what the inputs would need to be.
Run in backwards, so they say, but not really. Most things you'll write can't run backwards. You have to write them in a special way for that to be possible, and even then what it means is that you can do a depth first search to find the value.
There are some useful extensions like clpfd and asp but really if what you're doing is solving a constraint programming problem, you're much better of with OR-tools or MiniZinc.
Prolog is beautiful. I have practically no use for it. I've struggled to find something I can do better with Prolog than other tools, but I just love it aesthetically and that's enough for me sometimes.
3 replies →
How would this work with the XOR operator? Would it give all possible inputs?
1 reply →
It's also biased into informal definitions, mixing side effects with logic, and encapsulating complex behavior together. It's way more biased into being a scripting language, while Haskell has all those biases pointed at being an application language.
So, I'd say that both languages lead people into very different programing styles.