Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A Year of Functional Programming

japgolly.blogspot.com.au

Post reply on HN
Print view View original

41–50 of 172 posts

Re: A Year of Functional Programming

#41

Post by thirsteh »

Touche wrote: post #24
pron wrote: post #20

Earlier quoted context omitted.

Oh, absolutely. But I wasn't counting Clojure as FP in my comment. There is no definition for FP, and the OP seemed to be talking about the statically typed, pure FP, of Haskell and scalaz. Clojure is certainly not that kind of FP, as it's neither statically typed nor pure.

I know there are Haskell people who think Haskell is the only True Functional Language, but for the sake of discussion can we not go there?

It's not the only functional language by any means, but it is the strictest (he he.) It's silly arguing which is worth more, but it's also silly saying "Clojure is just as good as Haskell at separating effects."

Re: A Year of Functional Programming

#42

Post by bane »

cageface wrote: post #28
pron wrote: post #7

I used to like functional programming. Now I think that it's -- more often than not -- a solution in search of a problem. I can understand some of the things FP gets you (although those come at a cost, which I'll get to later); I'm just not so sure these are the things we need, or that FP is the best solution for them. One is code reuse: yes FP code is definitely more reusable. The problem is that the kind of code it…

The lack of magically bug-free, FP OSs, drivers, control software, and large applications, shows that even the biggest supposed benefits of languages like Haskell, are yet to be demonstrated in the real world. I've been reading religious advocacy of FP for almost 15 years now and yet there still don't seem to be many non-trivial apps written in any of these languages. Certainly many individual features of FP have bee…

They exist, but it's super spotty. HN is written in an FP language for example. One of the airline reservation systems is written in some kind of FP.

Reddit was written in a Lisp originally. But like many major FP projects, ended up being rewritten in a more common language. I used to work at a place that had hundreds of thousands of lines of CL code that was all rewritten in Perl and was on its way to getting rewritten into Java by the time I left there.

I agree with the major thrust of your argument, FP seems to find itself mired in weird niches. I'm not sure if it's because FP advocates seem to not want to write mainstream end-user software or it just hasn't leaked out into the mainstream, but it's pretty tough to find lots of major FP success stories outside of a constant stream of anecdotal advocacy stories (none of which ever seem to be attached to some piece of software I can download and actually touch for day-to-day usage).

I suspect the problem is that lots of the kind of software end users want is difficult/hard to write in an FP style, but an order of magnitude easier in an imperative language (even if it's less "right")...FP is just the wrong paradigm for general purpose programming, even if it works better than imperative languages in certain niches. I think this is an illuminating summary of all this [1]. However, here's an engine written in Haskell [2].

It seems that FP ideas will continue to end up in non-FP languages long before FP languages will become a major success. That might be a success by itself?

To save us some time, here are some pretty woeful lists where this exact question is asked and answered.

https://programmers.stackexchange.com/questions/22073/is-fun...

http://lambda-the-ultimate.org/node/2491

1 - http://prog21.dadgum.com/54.html

2 - http://www.hgamer3d.org/index.html

Re: A Year of Functional Programming

#43

Post by mark_l_watson »

cageface wrote: post #28
pron wrote: post #7

I used to like functional programming. Now I think that it's -- more often than not -- a solution in search of a problem. I can understand some of the things FP gets you (although those come at a cost, which I'll get to later); I'm just not so sure these are the things we need, or that FP is the best solution for them. One is code reuse: yes FP code is definitely more reusable. The problem is that the kind of code it…

The lack of magically bug-free, FP OSs, drivers, control software, and large applications, shows that even the biggest supposed benefits of languages like Haskell, are yet to be demonstrated in the real world. I've been reading religious advocacy of FP for almost 15 years now and yet there still don't seem to be many non-trivial apps written in any of these languages. Certainly many individual features of FP have bee…

Here is a good example of a complex Haskell app: the Haskell web based IDE at fpcomplete.com. They wrote the back end in Haskell and the client side with Haskell compiled to JavaScript. Really impressive.

Re: A Year of Functional Programming

#44

Post by bane »

outworlder wrote: post #35
cageface wrote: post #28

Earlier quoted context omitted.

The lack of magically bug-free, FP OSs, drivers, control software, and large applications, shows that even the biggest supposed benefits of languages like Haskell, are yet to be demonstrated in the real world. I've been reading religious advocacy of FP for almost 15 years now and yet there still don't seem to be many non-trivial apps written in any of these languages. Certainly many individual features of FP have bee…

> and yet there still don't seem to be many non-trivial apps written in any of these languages Perhaps you are not looking hard enough? Sure, if your problem space is CRUD web apps, then you won't find many implementations. Try looking into more difficult problem spaces, such as high-frequency trading, and you'll suddenly find more FP examples. Also, there's Erlang, which was developed by Ericsson to solve a very spe…

To be honest, I'd be happy with a 1 level interactive demo (with sound) of a Mario Brothers style platform game.

Re: A Year of Functional Programming

#45

Post by bkirwi »

jacquesm wrote: post #2

" Recently I looked at some code I wrote 8 months ago and was shocked! I looked at one file written in “good OO-style”, lots of inheritance and code reuse, and just thought “this is just a monoid and a bunch of crap because I didn't realise this is a monoid” so I rewrote the entire thing to about a third of the code size and ended up with double the flexibility. Shortly after I saw another file and this time thought…

If you're interested in examples of useful monoids and similar structures, you may want to have a look at the Algebird[0] project or the recent work on CRDTs[1]. The code savings in these projects comes from being able to write the complex distributed aggregation / conflict resolution / etc. code just once, and reuse it with a menagerie of useful implementations.

Personally, I like structuring things using these tools when I can get away with it. They're simple and broadly applicable abstractions, and mean I can reuse both my intuitions and my code in wildly diverse situations.

[0] https://github.com/twitter/algebird [1] http://highscalability.com/blog/2010/12/23/paper-crdts-consi...

Re: A Year of Functional Programming

#46

Post by mark_l_watson »

babs474 wrote: post #16
pron wrote: post #7

I used to like functional programming. Now I think that it's -- more often than not -- a solution in search of a problem. I can understand some of the things FP gets you (although those come at a cost, which I'll get to later); I'm just not so sure these are the things we need, or that FP is the best solution for them. One is code reuse: yes FP code is definitely more reusable. The problem is that the kind of code it…

I'm not sure about haskell, but in clojure the, run code, reason, run more code cycle is very much supported with the repl. In fact I find the nature of functional code very much helps out here. With clojure, in a complicated system I can typically take any subcomponent and run it in the repl without much fuss/mocking or worrying about the state of the system. Since usually functions aren't modifying state I can reru…

Like Clojure (which I have used a lot), Haskell development uses a repl (with really nice emacs support). For bottom up coding, I place a main function in every file with my test and experiments code; with an active repl in emacs it just takes a few seconds for the edit/run loop. In lower level code, I leave these main functions in place even though I am unlikely to need them once the code is working.

So, yes, Haskell and Clojure development has a similar flow.

Re: A Year of Functional Programming

#47

Post by mightybyte »

pron wrote: post #7

I used to like functional programming. Now I think that it's -- more often than not -- a solution in search of a problem. I can understand some of the things FP gets you (although those come at a cost, which I'll get to later); I'm just not so sure these are the things we need, or that FP is the best solution for them. One is code reuse: yes FP code is definitely more reusable. The problem is that the kind of code it…

> One is code reuse: yes FP code is definitely more reusable. The problem is that the kind of code it enables reuse of more than OO is very small, simple loops.

It sounds like you just haven't used Haskell enough to have the full extent of the reusability become apparent. I agree that on the surface it seems like you're right. But that particular example of reuse is just the tip of the iceberg. It's actually a very pervasive pattern that has tremendous positive impacts on your code at every level from small 3-line loops to large overarching abstractions.

This isn't just me making baseless assertions. It has been backed up by real world experience. There was an ICFP presentation by a company that rewrote their entire application in Haskell. With Haskell their reuse was an order of magnitude higher as measured by the number of external library dependencies! The rewrite also decreased the size of their code base by something like 80%. Oh, and they saw a massive reduction in bugs and increase in performance.

> But that premise has not been shown to be true. The lack of magically bug-free, FP OSs, drivers, control software, and large applications, shows that even the biggest supposed benefits of languages like Haskell, are yet to be demonstrated in the real world.

It's only been in the last 5 or so years that Haskell has really become commercially viable. This is too recent for the large apps you're talking about to have been written. But don't worry, we're working on it. The other day our newest hire made the comment that at our company each individual developer is responsible for roughly the equivalent of an entire team at all his previous jobs.

Re: A Year of Functional Programming

#48

Post by kasey_junk »

bane wrote: post #44
outworlder wrote: post #35

Earlier quoted context omitted.

> and yet there still don't seem to be many non-trivial apps written in any of these languages Perhaps you are not looking hard enough? Sure, if your problem space is CRUD web apps, then you won't find many implementations. Try looking into more difficult problem spaces, such as high-frequency trading, and you'll suddenly find more FP examples. Also, there's Erlang, which was developed by Ericsson to solve a very spe…

To be honest, I'd be happy with a 1 level interactive demo (with sound) of a Mario Brothers style platform game.

That is sort of the worst case scenario for a FP program (though I'm sure you could write it in FP). It is almost entirely side-effects.

I agree with the sentiment that for a paradigm that has been advocated for 60 years it is really odd how little non-academia code is written in it.

In my experience you find functional code shines (and is therefore common) in places where prove-ability is of the utmost importance or where writing custom DSLs provide a lot of value. Things like nuclear systems, extremely high security applications (think custom OS level requirements) or financial modelling software.

That said in most of the places I've found the FP program is a high value prototype or proof of concept, not the actual system. I don't know if that is just a resource allocation thing or not.

Re: A Year of Functional Programming

#49

Post by interknot »

bane wrote: post #44
outworlder wrote: post #35

Earlier quoted context omitted.

> and yet there still don't seem to be many non-trivial apps written in any of these languages Perhaps you are not looking hard enough? Sure, if your problem space is CRUD web apps, then you won't find many implementations. Try looking into more difficult problem spaces, such as high-frequency trading, and you'll suddenly find more FP examples. Also, there's Erlang, which was developed by Ericsson to solve a very spe…

To be honest, I'd be happy with a 1 level interactive demo (with sound) of a Mario Brothers style platform game.

There's Nikki and the Robots:

http://joyridelabs.de/game/

There's also Super Monao Bros (which used to be called Super Nario):

https://github.com/mokehehe/monao/tree/master

Re: A Year of Functional Programming

#50

Post by Tyr42 »

bane wrote: post #44
outworlder wrote: post #35

Earlier quoted context omitted.

> and yet there still don't seem to be many non-trivial apps written in any of these languages Perhaps you are not looking hard enough? Sure, if your problem space is CRUD web apps, then you won't find many implementations. Try looking into more difficult problem spaces, such as high-frequency trading, and you'll suddenly find more FP examples. Also, there's Erlang, which was developed by Ericsson to solve a very spe…

To be honest, I'd be happy with a 1 level interactive demo (with sound) of a Mario Brothers style platform game.

Niki and the Robots[1]

[1]: http://joyridelabs.de/game/trailer/

Post reply on HN