The unification-fd package

unification-fd
==============

This is a simple package and should be easy to install. You should
be able to use one of the following standard methods to install it.

    -- With cabal-install and without the source:
    $> cabal install unification-fd
    
    -- With cabal-install and with the source already:
    $> cd unification-fd
    $> cabal install
    
    -- Without cabal-install, but with the source already:
    $> cd unification-fd
    $> runhaskell Setup.hs configure --user
    $> runhaskell Setup.hs build
    $> runhaskell Setup.hs test
    $> runhaskell Setup.hs haddock --hyperlink-source
    $> runhaskell Setup.hs install

The test step is optional and currently does nothing. If you see
some stray lines that look like this:

    mkUsageInfo: internal name? t{tv a7XM}

Feel free to ignore them. They shouldn't cause any problems, even
though they're unsightly. This should be fixed in newer versions
of GHC. For more details, see:

    http://hackage.haskell.org/trac/ghc/ticket/3955

If you get a bunch of type errors about there being no MonadLogic
instance for StateT, this means that your copy of the logict library
is not compiled against the same mtl that we're using. To fix this,
update logict to use the same mtl.


Portability
===========

An attempt has been made to keep this library as portable as possible,
but it does rely on some common language extensions (i.e., ones
implemented by Hugs as well as GHC) as well as a couple which are
only known to be supported by GHC. All required language extensions
are:

    Rank2Types
    MultiParamTypeClasses
    FunctionalDependencies -- Alas, necessary for type inference
    FlexibleContexts       -- Necessary for practical use of MPTCs
    FlexibleInstances      -- Necessary for practical use of MPTCs
    UndecidableInstances   -- Needed for Show instances due to two-level types

----------------------------------------------------------- fin.