Release notes for version 2.04 -- 6/97

• 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 `Andr\'e Santos <alms@di.ufpe.br>' have been included, AIX/RS6000 is now a supported `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.