[Yhc] Warning: Yhc.Core Binary Format changing

[Neil Mitchell]

Hi,

The Yhc.Core Binary format is about to change, the Haskell interface
will remain the same - but you'll need to recreate all core files you
have floating around - anything .ycr or .yca. I am sorry to say that
opening an old Core file with the new instances seems to
non-terminate, rather than giving an error message. This is
unfortunate, but hopefully future Core changes should not have this
side effect.

The reason for this change is the move from our hand-made Binary
instance to the standard Data.Binary one. This should give us a speed
up, and means we are keeping less of our own code in our tree. It
probably means that we require either GHC 6.6 or the fps package to be
installed on GHC 6.4.

This change also means that to generate the Binary instance we are no
longer relying on DrIFT but instead on Derive [1]. This means that
anyone should be able to regenerate the Binary instance, rather than
just me with a weird batch file.

Thanks

Neil

[1] http://www-users.cs.york.ac.uk/~ndm/derive/