It's not quite so simple in the case of GHC. The runtime is where the problem is. It's got a lot of special (potentially handwritten/target-specific stuff) th

It's not quite so simple in the case of GHC. The runtime is where the problem is. It's got a lot of special (potentially handwritten/target-specific stuff) that gets baked into Haskell programs (which is why a lot of trivial Haskell program binaries are so big). I think that the creators of tools like this would consider this an optimization for later iterations. The application/integration of asm.js would be two-fold for them. The (non-trivial) runtime that Haskell uses would need to be rewritten by hand in asm.js and the compiler would need to be reconfigured to emit asm.js. I want to see asm.js, too. I think these two things create a big bucket of work that the initial creator of the compiler doesn't want to implement up front. I'm a bit interested in contributing to this. Maybe I can learn me some asm.js and see what I can do :-).