patch applied (cabal-install): Change the DependencyResolver type to take a per-package version pref

[Duncan Coutts]

Mon Jun  2 11:24:10 PDT 2008  Duncan Coutts <duncan at haskell.org>
  * Change the DependencyResolver type to take a per-package version pref
  And add a few global package version pref policies and use them in
  ordinary install and upgrade. For install we use a policy that says
  that we prefer the latest version of a package that we specifically
  request and prefer the installed version of any other package. For
  upgrade we simple always prefer the latest version. One can imageine
  other policies where we prefer the latest version for only some
  interesting subset of packages and installed otherwise.
  No resolvers actually make use of this preference yet.

    M ./Hackage/Dependency.hs -11 +60
    M ./Hackage/Dependency/Bogus.hs -1 +1
    M ./Hackage/Dependency/Naive.hs -1 +1
    M ./Hackage/Dependency/TopDown.hs -3 +5
    M ./Hackage/Dependency/TopDown/Types.hs -2
    M ./Hackage/Dependency/Types.hs +13
    M ./Hackage/Fetch.hs -3 +4
    M ./Hackage/Install.hs -4 +7

View patch online:
http://darcs.haskell.org/cabal-install/_darcs/patches/20080602182410-adfee-2c042ecc02c7c9b9bf99400559b7d69dc8757148.gz