are you a student (undergrad or grad) or faculty (junior or senior)? These are all very different scenarios and accordingly different goals are realistic. For example, if you're a student, it might be more realistic to start with finding a professor who will be willing to supervise an independent study class. On Sun, Aug 2, 2009 at 6:25 AM, Petr Pudlak wrote:

Hi all,

I'd like to convince people at our university to pay more attention to functional languages, especially Haskell. Their arguments were that

(1) Functional programming is more academic than practical. (2) They are using logic programming already (Prolog); why is Haskell better than Prolog (or generally a functional language better than a logic programming language)?

(1) is easier to answer, there are a lots of applications at HaskellWiki, or elsewhere around the Internet, written in Haskell, OCaml, etc. Still, I welcome comments on your experience, for example, if you have written some larger-scale application in Haskell (or another a functional language) that is not at HaskellWiki, and perhaps if/why you would recommend doing so to other people.

(2) is harder for me, since I've never programmed in Prolog or another language for logic programming. I'd be happy if anyone who is experienced in both Prolog and Haskell could elaborate the differences, pros & cons etc.

Thanks, Petr _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

On Sun, 2009-08-02 at 12:25 +0200, Petr Pudlak wrote:

(2) is harder for me, since I've never programmed in Prolog or another language for logic programming. I'd be happy if anyone who is experienced in both Prolog and Haskell could elaborate the differences, pros & cons etc.

I have done some "real-world" programming in Prolog and SML. The conventional wisdom in the LP community seems to be that the primary path to performance improvement of logic programs is by reduction of non-determinism. To a first approximation, when you have eliminated all the non-determinism from a logic program what you have left is a functional program. The work I was involved with, trying to get quasi-real-time performance from Prolog, bore this out. -- Bill Wood

On Sun, Aug 2, 2009 at 12:25 PM, Petr Pudlak wrote:

I'd like to convince people at our university to pay more attention to functional languages, especially Haskell. Their arguments were that

(1) Functional programming is more academic than practical. (2) They are using logic programming already (Prolog); why is Haskell better than Prolog (or generally a functional language better than a logic programming language)?

Regarding (1), today it's common to do functional programming in "industrially accepted" languages, at least if you want to be productive :) Take for example the following C# code, taken from production code: var graphs = selection.SelectMany( e => e.SelfAndIntraGraphAncestors() .OfType<IGraphContainer>() .Take(1) .SelectMany(gc => gc.ChildGraphs)); Each of these C# methods work on lazy streams, so this even lazy functional programming in a sense :) (albeit with potential side effects) I could write this in imperative style, something like this (but it's not the same, the code below is strict, a lazy version would be much longer, unless I cheat and use C#'s yield statement) var graphContainers = new List<IGraphContainer>(); foreach( var entity in selection ) { foreach( var ancestor in entity.SelfAndIntraGraphAncestors() ) { var graphContainer = ancestor as IGraphContainer; if( graphContainer != null ) { foreach( var childGraph in graphContainer.ChildGraphs ) { graphContainers.Add(childGraph); } break; } } } Obviously the second one is much less declarative and more difficult to read (and maintain). So really, any good industrial programmer should master at least the basics of functional programming. Haskell might be one of the most beautiful and elegant languages to use for learning functional programming. Also IMHO any experienced programmer should understand that although popular imperative programming languages like C++, C#, Java, Python, etc are more "powerful" than pure functional languages (in these sense that you can peek and poke around without restrictions like a crazy chicken), in practice this power is so difficult to control that it's a bit like giving everybody the right to carry a gun in public so people would feel safer ;-)