This is the release notes for GHC-2.04, describing what's new since the
previous release:

GHC 2.04 is a minor upgrade of GHC 2.02 (and the bugfix release,
2.03), representing work done through May '97. This new release
adds the following:

* Data constructors can now have polymorphic fields, and ordinary
  functions can have polymorphic arguments.  Details on

    http://www.cse.ogi.edu/~simonpj/quantification.html

  Existential types coming, but not done yet.

* Pattern guards implemented, see
	
   http://www.cse.ogi.edu/~simonpj/guards.html

* Compiler can now compile itself.

* INLINE pragmas honoured (caveat: not yet
   working on instance-decl methods) 

* Simplifier improvements and better inlining gives
   better code; not sure how *much* better.

* -dshow-rn-stats print out amusing statistics about what
  the renamer does.

* When compiling without -O, the renamer (the pass responsible for
  slurping in interface file and making sure everything is in scope
  etc.) is now more careful about what it will bring in (especially
  data constructors and instance declarations). The upshot of this
  change is that a lot of the (unnecessary) work this pass did in
  2.02/2.03 is now avoided.

  -fno-prune-tydecls and -fno-prune-instdecls switch off these
  renamer optimisations. You can try the effect with the renamer
  statistics. War stories welcome.

* The Heroic Efforts of \tr{Andr\'e Santos <alms@di.ufpe.br>} have
  been included, AIX/RS6000 is now a supported \tr{ghc}
  platform! Bug reports concerning this port to (as always)
  glasgow-haskell-bugs@dcs.gla.ac.uk

* A lot of the bugs that were present in versions 2.02/2.03
  have been fixed (thanks to everyone that reported bugs!).
  A list of the reported problems with 2.02/2.03 can be found at

    http://www.dcs.gla.ac.uk/fp/software/ghc/ghc-bugs.html

    No doubt entries for 2.04 will be added here as well :-)

* This release is available in source format only. To build it you'll
  need to have either a copy of GHC~0.29 or GHC~2.02/3 installed.
  For people either doing porting work or work on a (supported) 
  platform for which there is no GHC binary bundles available, the
  necessary intermediate files are also available (.hc and .hi files).

  Consult the installation guide for more information on how
  to build or bootstrap. The guide is included in the distribution
  (in the fptools/docs directory), and an on-line version of the
  document can be found at

    http://www.dcs.gla.ac.uk/fp/software/ghc/ghc-doc/install-guide.html


In addition to the above, we've made the following minor changes to
the GHC libraries/our implementation of the Haskell standard prelude:

* `isPrefixOf' and `isSuffixOf' has been added to `List'
* The empty type `Void' is now exported from the prelude.
* `GlaExts' exports the `Lift' data type:

    data Lift a = Lift a

  you might need it someday...

* The `Foreign' interface now also exports the representations
  for `Word' and `Addr'

* The low-level file handle interface in the POSIX system
  library has been reworked a bit, most notably is the renaming of
  `Channel' to `Fd' and the introduction of operations for converting
  to and from `Handle' and `Fd' values. The changes are:

   --Renamed functions (old name in square brackets)
   openFd :: FilePath       
          -> OpenMode 
          -> Maybe FileMode 
          -> OpenFileFlags 
          -> IO Fd
    -- [openChannel]
   fdSeek  :: Fd -> SeekMode -> FileOffset -> IO FileOffset 
    --[seekChannel]
   fdRead  :: Fd -> ByteCount -> IO (String, ByteCount)     
    --[readChannel]
   fdWrite :: Fd -> String -> IO ByteCount                  
    --[writeChannel]
   fdClose :: Fd -> IO ()          
    --[closeChannel]
   setFdOption :: Fd -> FdOption -> Bool -> IO ()
    --[setChannelOption]
   queryFdOption :: Fd -> FdOption -> IO Bool
    --[queryChannelOption]
   dup :: Fd -> IO Fd
    --[dupChannel]
   dupTo :: Fd -> Fd -> IO ()
    --[dupChannelTo]

   data FdOption = AppendOnWrite | CloseOnExec | NonBlockingRead
    --[ChannelOption]
   getFdStatus :: Fd -> IO FileStatus
    --[getChannelStatus]

   -- New data structure collecting together misc flags passed to openFd
   data OpenFileFlags =
    OpenFileFlags {
      append    :: Bool,
      exclusive :: Bool,
      noctty    :: Bool,
      nonBlock  :: Bool,
      trunc     :: Bool
    }

   --New ops for converting between Fd and Handle:
   fdToHandle :: Fd -> IO Handle
   handleToFd :: Handle -> IO Fd
   intToFd    :: Int -> Fd -- use with care.