Haskell [Was: Re: A few comments about D]

[Timon Gehr]

On 08/24/2011 08:19 PM, Jonathan M Davis wrote:
> On Wednesday, August 24, 2011 04:22 bearophile wrote:
>> Caligo:
>>> Haskell is one of the most beautiful languages. I wish I had discovered
>>> it sooner.
>>
>> I am now able to write small Haskell programs. It has some features and
>> parts that I like significantly (and I'd like some of them in D too!), but
>> so far I am not appreciating it much on the whole. It feels almost like a
>> "puzzle language", as Forth (almost, but not really). Those operators are
>> not easy to find in the documentation, the purpose of all those little
>> functions is not easy to remember, and its obsession with purity sometimes
>> turns easy things into very complex things (I like purity and
>> immutability, but not much inside functions, so I prefer D). It's good for
>> some kinds of tasks (Euler Puzzles, certain math tasks, certain
>> experiments about types), acceptable for other tasks (some generic
>> algorithms, some string processing, etc), and bad for many other purposes,
>> so it doesn't feel like a general purpose language. I am sometimes able to
>> write very short programs with it, but often they are slow. It's not easy
>> for me to tell how much efficient a program will be, onc! e compiled with
>> GHC. Keep in mind that I am a newbie of Haskell, so don't take my comments
>> too much seriously :-)
>
> I like Haskell and have used it a fair bit, but I don't use it a lot these
> days. I think that every serious programmer should study and learn at least
> one functional language. Learning to think functionally can have be very
> helpful even in imperative programming and will make you a better programmer.
> And on top of the kind of stuff that it normally helps with (like
> understanding recursion), in D it helps when dealing with ranges, since ranges
> can be processed like slists a lot of the time.
>
> However, as much as I like Haskell, I find it very hard to work with on
> anything large, and even smaller stuff can be difficult. It just requires too
> much brain-bending to figure out how to do something purely functionally for
> it to be easy, and Haskell's laziness makes debugging it very difficult.
>
> So, I definitely recommend learning a functional lanugage (and Haskell is a
> good one), but I wouldn't program in it as my primary language. The main
> reason that I've used it as much as I have is that it has a fantastic parsing
> library (Parsec). And actually, I've been working on trying to port it to D,
> though it'll probably be a while before I finish it, and the lack of laziness
> could actually be a performance impediment in this case, since you risk having
> to copy the parsing state too often. Hopefully I can get that sorted out
> though. I still have a ways to go with it regardless.
>
> - Jonathan M Davis

I have implemented runtime lazy lists on top of delegates as a toy 
project. I have also written some utility lazy functions, a purely 
functional lazy merge sort to sort the lists and a recursively defined 
fibonacci list that works in O(n). Unfortunately it is about 10 times 
slower than haskell. :)

And the syntax sucks, much owed to
http://d.puremagic.com/issues/show_bug.cgi?id=6260

If anyone is interested:

http://pastebin.com/2rEdx0RD