Re: [Haskell-cafe] [reactive] A pong and integrate

The GHC bugs are now fixed, so it might be stable enough for another adventure like that, but I don't think I would bet on it again.

GHC bugs are corrected, but Reactive still have some. (See my previous posts)

IMO Haskell is great for writing small clean prototypes, doing interesting research, and maybe making some fun little games, but I wouldn't use it for production reactive game coding, not yet at least.

Tim Sweeney (from Epic Games) has another perspective about that [1]. Besides, FRP is not mandatory. You can always make games in Haskell by using a more regular style (more "imperative", would some say). For now, the main problem is the small number of Haskell libraries for games when compared to the huge numbers of those which exist in C++, which prevents, for now, Haskell to be used as the main language for big commercial games. But for smaller scale games (like indie), which have less needs, I think it's worth it. [1] http://www.scribd.com/doc/5687/The-Next-Mainstream-Programming-Language-A-Ga... 2010/5/25 Peter Verswyvelen

Well, first of all, I did not make these PS3 visualization, my former colleagues and I just made the editor, language and runtime that allowed video game artists to do the job for us in a couple of weeks time :-)

I wouldn't use Yampa, for performance reasons, and difficulty to get it running on alien platforms (it is well known it performs relatively badly, although the work done by Paul Liu and co on Causal Commutative Arrows looks very promising, but does not support dynamic switching yet). After all, Yampa models a synchronous dataflow language, and compilers for these languages are relatively easy to make IMO.

My previous - now defunct - company Anygma spent a lot of money on trying to use Haskell and Reactive for game programming, which unfortunately ended in some nasty GHC bugs popping up (see http://www.haskell.org/haskellwiki/Unamb), and not all problems with Reactive got fixed; it is amazing how difficult this all turned out to be. The GHC bugs are now fixed, so it might be stable enough for another adventure like that, but I don't think I would bet on it again.

IMO Haskell is great for writing small clean prototypes, doing interesting research, and maybe making some fun little games, but I wouldn't use it for production reactive game coding, not yet at least.

On Tue, May 25, 2010 at 10:49 AM, Limestraël wrote:

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Wow... impressive...

And now, with your experience, if you'd have to do this again, would you use Yampa or stick up with C#/C++ ?

2010/5/24 Peter Verswyvelen

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Yeah. Funny that we're still writing games in C++, while mission critical and hard real time systems are written in much nicer languages :)

I made something similar to Lucid Synchrone for a game company I used to work, but with the purpose of making reactive programming accessible to computer artists. The integrated development environment provided the typical boxes-and-links user interface, where the boxes were signal functions. Signals itself were not exposed, like Yampa. The system did type inference so artists never really had to deal with types. Special nodes like feedback and delay where provided to allow transferring values to the next frame. This actually was a great success, digital artists could literally create little interactive applications with it, without much help from programmers. This resulted in a Playstation 3 visual experience "Mesmerize" (http://www.youtube.com/watch?v=rW7qGhBjwhY). This was before I knew Haskell or functional programming, so it was hacked together in C# and C++...

I still believe that the reason why computers artists could work with this environment and were not able to learn imperative programming is functional programming itself: the system had all the goodies of FP: type inference, referential transparancy, etc... But is also provided the possibility to edit literals while the simulation was running, providing zero turnaround times, which was equally important for quick adoption of the software.

So IMO Haskell and FRP systems have a huge potential for education of a much broader audience than just computer scientists...

On Mon, May 24, 2010 at 6:13 PM, Limestraël

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I assumed also that it was a field which was still under research, however, Lustre, again, is used "for critical control software in aircraft, helicopters, and nuclear power plants", according to wikipedia.