Interchange structured data between Haskell and C

Question

First, I\'m a Haskell beginner.

I\'m planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complex

Answer 1

Even though you can get deterministic memory layout for strict unboxed Haskell structures, there are no guarantees and it is a really really bad idea.

If you're willing to live with conversion, there's Storeable: http://www.haskell.org/ghc/docs/6.12.3/html/libraries/base-4.2.0.2/Foreign-Storable.html

What I'd do is construct the C structures, and then construct Haskell functions that operate directly on them using the FFI, rather than trying to produce Haskell "equivalents" to them.

Alternately, you can decide that you only need to pass a select bit of information to the C -- not the whole game state, but just a few pieces of information about what objects are where in the world, with your actual information on how to draw them living solely in the C side of the equation. Then you do all the logic in Haskell, operating on native Haskell structures, and only project out to the C world that tiny subset of data which the C actually needs to render with.

Edit: I should add that matrices and other common c structures already have excellent libraries/bindings that keep the heavy lifting on the c side.