Casey Basichis wrote:

I'm not entirely sure what you mean.

I'm intending on using Ogre for GUI - for which there is the Hogre bindings, but after emailing the DEV about it, I didn't get the impression from his advice that I should be using it for production code. Here is what he suggested:

"It depends, really. Hogre is good for running Ogre from within Haskell, but it has its limitations. The number one thing people have been struggling with is handling input with hogre - there's Hois (Haskell wrapper for OIS) but it's not perfect (it misses input events), and the other option is having to write some C++ glue. Hogre is a solid proof of concept and you can do some demos with it, but if you're e.g. writing a game it might be a bit of a struggle. In the end it's about how much you value being able to write code in Haskell (or how allergic to C++ you are)."

I'm on iOS so I imagine those difficulties are compounded.

I am using several other C++ libraries for which there are no existing bindings and no Haskell alternative packages that are even remotely close.

Are you suggesting it would be better to write all my own FFI bindings for all the needed libraries?

That's not what I'm suggesting. It was just too little information to properly judge the difficulty of doing everything in Haskell. Binding to Ogre (or C++ in general) is indeed difficult. If Hogre doesn't work or is too limited, your best option might be to write a C wrapper around the Hogre functionality you need. Another option is to use SDL/OpenGL directly, which may be easier or harder depending on your application. However, if you can build the bridge between your rendering library and Haskell, then Haskell is certainly the better choice.

Everything I read suggests that Haskells strengths are in transformation and that interaction is not its strong suit.

I am interested in your thoughts and I am open to whatever, but you are the first to suggest that the mix is a bad idea.

That used to be true, but the reason has nothing to do with the language. The problem was that the libraries weren't there. Nowadays you can write all sorts of interactive applications in Haskell, including GUIs, TUIs, games, simulations and web applications. However, I've long been waiting for useful bindings to Ogre or Irrlicht, but I'm afraid that it's not going to happen any time soon. Ultimately it's your choice. Let me summarize the possiblities: * C wrapper around Ogre. Easy integration, but need to write the rendering code in C/C++. * Full FFI bindings to Ogre. Difficult integration, but you can write your rendering code in Haskell. * Partial FFI bindings to Ogre. Integration may be somewhat easy, if you do the initialization in Haskell and the actual rendering in C/C++. However, this again requires to write the rendering in C/C++. * Using SDL/OpenGL directly: Everything available for Haskell. May be difficult, because you need to write OpenGL code. I hope, this helps. Greets, Ertugrul -- Key-ID: E5DD8D11 "Ertugrul Soeylemez " FPrint: BD28 3E3F BE63 BADD 4157 9134 D56A 37FA E5DD 8D11 Keysrv: hkp://subkeys.pgp.net/

Quoth Casey Basichis , ...

I am using several other C++ libraries for which there are no existing bindings and no Haskell alternative packages that are even remotely close.

Are you suggesting it would be better to write all my own FFI bindings for all the needed libraries?

Everything I read suggests that Haskells strengths are in transformation and that interaction is not its strong suit.

I've done it, for my own amusement - wrapped a C++ graphics toolkit and used it to write a couple small applications. Most of us would probably object to your transformation/interaction evaluation as presented above ... but it depends on your motivations. In my case, I simply wanted to use Haskell, and in fact I started with a model like yours where the UI was simply written in C++. There were some very cumbersome things about that arrangement though, so I was happy to integrate Haskell into the UI as soon as it became possible. On the other hand ... I'd be lying if I said the Haskell code is "cleaner", or really advantageous in any compelling way if we're just talking about the UI. It has its moments - Haskell is always going to pull a few things off pretty well, in a UI or whatever - but of course, this particular UI API is specifically more suited to C++, than Haskell. So given that one can write good, clean code in C++, too, the question is whether Haskell is so vastly advantageous for such applications that it compensates for the sketchy binding. It isn't, I think. Whereupon we come to your original question. Personally, I would just work with the model that's natural to your API. If it's a C++ OO 3D graphics library, then go OO, for the very same reasons discussed above. FP may in principle have all the virtues mentioned in that article, and it's good to be on the lookout for ways you can deploy some of that in a C++ program, but when it comes time to use that OO API, it's what you've got. Donn