[Haskell] Re: [Haskell-cafe] ANN: cmonad 0.1.1

[Simon Peyton-Jones]

Lennart,

| Unfortunately, GHC lacks certain optimizations to make efficient code
| when using CMonad,
| so instead of C speed you get low speed.
...
| When I looked at it a year ago or so, it was a return of one
| constructor in a sum.
| Looking at core, you can see several places where a function is called
| and that function always returns the same constructor, so the case
| analysis of the return value is not needed; it should be returned as
| an unboxed tuple instead
| I'll see if I can get a simple example to illustrate the problem.

That would be very helpful, thanks.  Having a Trac ticket with a small reproducible test case, and a pointer to a larger example that illustrates its importance, would be great.  Indeed, it is pervasive, or can you try the effect of performing the transformation by hand, and seeing if it makes a difference?

That doesn't guarantee that I, or anyone else, will get to it, but it makes it much much more likely!

Simon