cvs commit: fptools/ghc/lib/std PrelIO.hsc

[Simon Marlow]

> Mon, 17 Sep 2001 09:21:41 -0700, Simon Marlow=20
> <simonmar@glass.cse.ogi.edu> pisze:
>=20
> >   Subvert GHC's full-laziness optimisation by explicitly=20
> lambda-lifting
> >   a local lambda expression to the top level, and exporting=20
> it to ensure
> >   it doesn't get inlined.
>=20
> Why would {-# NOINLINE #-} not work?

Yes, that would be a better way to do it.

> >   Without this hack, full-laziness will float out several
> >   subexpressions, which turns out to be a pessimisation in=20
> this case.
>=20
> Is it possible to improve the compiler for such cases?

Keith Wansborough's usage type system is designed to handle these cases,
but it's a way off being ready.  We've been discussing other ways of
getting some of the benefit without too much work, but haven't settled
on anything yet.

Cheers,
	Simon