Performance Timing

[Simon Marlow]

> timer f a =3D do
>   t1 <- get current time
>   evaluate (f a)
>   t2 <- get current time
>   return (different in t2 and t1)
>=20
> where evaluate is from Control.Exception.  could someone tell me how
> evaluate compares to seq and deepSeq?

The documentation explains the difference, but it's a bit cryptic.

Informally: 'evaluate e' is an IO action that, when performed, forces e
to weak-head normal form.  It's a kind of seq that you can use in the IO
monad.

Cheers,
	Simon