Optimisation of unpackCString#

[Ian Lynagh]

On Mon, Apr 28, 2008 at 02:00:38PM -0700, Donald Bruce Stewart wrote:
> 
> This goes back to an old gripe of mine actually -- we can't get
> at the length of a C string literal at compile time either, which
> would be super useful in rules.

I think that this is easy to do by, instead of desugaring

    "foo" -> unpackCString# "foo"#

desugaring

    "foo" -> unpackCStringLen# 3# "foo"#

where

    unpackCStringLen# _ = unpackCString#

It's not really feasible to do head#, tail# etc this way, though, so if
head#/tail# are done another way then it's probably best to do length#
that way too.

By the way, please do file tickets for the issues from this thread, so
that the issues and ideas don't get forgotten about!


Thanks
Ian