Comment by Spyro7 | Hacker News Reader

Comment by Spyro7 | Hacker News Reader

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"Functional programming is just the general notion of using more functions, and less computer-architectury things, to express your ideas."

Umm, no, that is not what functional programming is. Functional programming is, basically, programming without side-effects. A purely functional language will have variables that are completely immutable. This is a bit of a shift away from the way things are done in C or C++.

Speaking just for myself, I started into the programming world with Java (not counting QBasic), and I am finding it incredibly hard to wrap my brain around the idea of functional programming.

My understanding is that most programmers that have a background primarily working with non-functional languages have a challenging time initially grasping the concepts of functional programming. However, I would guess that a programmer that learns a functional programming style early on would probably have very little difficulty understanding non-functional constructs.

For more information, I would like to point you towards some easy reading:

* http://en.wikipedia.org/wiki/Side_effect_(computer_science)

* http://learnyouahaskell.com/introduction#so-whats-haskell

Edit: To whoever down-voted me, I would appreciate some explanation of your views. The fact is that functional programming is not just using functions. The article plainly refers to functional programming languages and not simply using functions. There is a difference.

I don't ninja downvote, but if I had to guess I'd say it's because if you're finding functional programming incredibly difficult, you maybe shouldn't be lecturing on what it is.

As my cousin points out, it's true that it's easy to think of functions as just being macros in a language like C. If you call a function which doesn't have a return value, and which modifies some global state, that's not a "real" function, just a stored procedure.

However, if you write a C function which doesn't modify global state, but simply takes an input and returns an output, as even novice programmers do all the time, hey presto— that's the functional paradigm! There's nothing mystical about it, and what the GP is saying is that telling people who have done this that functional programming is something different is fundamentally confusing.

"I'd say it's because if you're finding functional programming incredibly difficult, you maybe shouldn't be lecturing on what it is."

Thank you for your thoughtful reply. I really do appreciate it.

It isn't the programming that is the hard thing. Writing some code to do something meaningful is not what is giving me a problem. Actually, it is trying to develop a deep understanding of functional programming that I am finding difficult. Maybe the problem is that I am confusing functional programming with purely functional programming?

My apologies to tumult if it came off that I was lecturing in my original post. I find it challenging to get tone perfectly right on the Internet. Face to face conversation or conversation over a phone is far better.

I think maybe this entire thread comes down to a question of semantics. When I program in non-functional languages I tend to lean towards using map/reduce type constructs a lot, but I never really thought of that as "functional programming". I guess I always thought that in order to really do functional programming, you really needed to have some kind of deep understanding of it.

Maybe if I had a formal computer science background, my perspective would be a little bit different because I would have more easily seen the point that you are making. As it stands, my background is in the social sciences and my knowledge of the science part of computer science is sometimes lacking.

Perhaps you are right, I should have been better informed before attempting to inform others. But if I had not typed my original post, then I would have never received your helpful reply and I would still be in the dark!

Maybe the problem is that I am confusing functional programming with purely functional programming?

Yeah, you nailed it. Writing a whole program with purely functional constructs is a little mind bending, since procedurally fundamental things like "printf" don't really exist. But that's just something that's much easier to do procedurally; it's hard for everyone, and there's no real secret to understanding it.

The important thing to remember is that languages don't have just one paradigm. An imperative language with first-class functions (as most high-level scripting languages have) is functional, just not "as" functional as, say, Haskell. You can use functional concepts in a language which isn't purely functional, just like you can use OO concepts in a language which isn't purely OO.

The good news is it sounds like you get functional programming much more than you thought, and you've definitely got the right attitude towards learning.

As long as you're open to being corrected, and honest about the limits of your knowledge, there's nothing wrong with trying to teach something you don't fully understand yourself. Teaching is one of the best ways to learn. Keep it up :)

+1. I fat thumbed you and downvoted, so sorry!

  My understanding is that most programmers that have a background primarily working with non-functional languages have a challenging time initially grasping the concepts of functional programming.

I'd guess that "most programmers that have a background primarily working with non-functional languages" could just be shortened to "most programmers". Take a look at any of the "language ranking" pages around and you'll find that they're all dominated by imperative/procedural languages.

  However, I would guess that a programmer that learns a functional programming style early on would probably have very little difficulty understanding non-functional constructs.

You're right; unfortunately, it seems that most CS curriculums these days just rush people through some basic programming classes in Java/Python (maybe C++) then through a few more "upper level" electives while just skimming over the algorithmic and data structures stuff that FP is most useful for.

I'd argue that the algorithmic / data structures material (maybe with an intro to some FP language mixed in) is much more important than those elective classes, because the elective stuff is much easier to pick up later on (as needed), while someone who doesn't know their algorithms could spend a whole career writing buggy, slow code because of it.

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