File searching

Hi Folks, I've attached a Haskell module that describes GHC's file searching strategy in the form of a simplified implementation, which serves as a precise description of what GHC actually does. I'm hoping we can use this as a starting point from which to discuss extensions. I've already added two extensions (see the source for details). The simulation is complete, in that it covers what happens with packages, what happens when you name a source file on the command-line, what happens with files named in a ':load' command in GHCi, and so on. All the various flags affecting GHC's search behaviour can also be tweaked. Enjoy... Cheers, Simon