-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | provide access to the Hackage database via Data.Map
--   
--   This module provides simple access to the Hackage database by means of
--   <tt>Data.Map</tt>. Suppose you wanted to implement a utility that
--   queries the set of available versions for a given package, the
--   following program would do the trick:
--   
--   <pre>
--   import qualified Distribution.Hackage.DB as DB
--   import Distribution.Text ( display )
--   import System.Environment ( getArgs )
--   
--   main :: IO ()
--   main = do
--     pkgs &lt;- getArgs
--     db &lt;- DB.readHackage
--     let getVersions name = maybe [] DB.keys (DB.lookup name db)
--     mapM_ (putStrLn . unwords . map display . getVersions) pkgs
--   </pre>
--   
--   When run, it would produce the following output:
--   
--   <pre>
--   ./a.out containers deepseq cabal-install
--   0.1.0.0 0.1.0.1 0.2.0.0 0.2.0.1 0.3.0.0 0.4.0.0
--   1.0.0.0 1.1.0.0 1.1.0.1 1.1.0.2
--   0.4.0 0.5.0 0.5.1 0.5.2 0.6.0 0.6.2 0.6.4 0.8.0 0.8.2 0.10.0 0.10.2
--   </pre>
--   
--   Note that once the database has been parsed, it can be accessed
--   quickly, but the inital cost of reading <tt>00-index.tar</tt> is
--   fairly high.
--   
--   This package is known to work on Linux and Mac OS X, but not Windows.
@package hackage-db
@version 1.7


-- | This module provides simple access to the Hackage database by means of
--   <a>Map</a>. Note that once the database has been parsed, it can be
--   accessed quickly, but the inital cost of reading <tt>00-index.tar</tt>
--   is fairly high.
module Distribution.Hackage.DB

-- | A <a>Map</a> representation of the Hackage database. For sake of
--   simplicity, we use <a>String</a> rather than <a>PackageName</a> to
--   represent the name of a package.
type Hackage = Map String (Map Version GenericPackageDescription)

-- | Read the Hackage database from <tt>$HOME/</tt><i>&lt;package database
--   path&gt;</i><tt>/hackage.haskell.org/00-index.tar</tt> and return a
--   <a>Map</a> that provides fast access to its contents. That
--   <tt>tar</tt> file is typically created by running the command
--   <tt>"cabal update"</tt>.
readHackage :: IO Hackage

-- | Read the Hackage database from the given <a>FilePath</a> and return a
--   <a>Hackage</a> map that provides fast access to its contents.
readHackage' :: FilePath -> IO Hackage

-- | Parse the contents of Hackage's <tt>00-index.tar</tt> into a
--   <a>Hackage</a> map.
parseHackage :: ByteString -> Hackage