content: -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Package
  -- Copyright   :  Isaac Jones 2003-2004
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- Defines a package identifier along with a parser and pretty printer for it.
  -- 'PackageIdentifier's consist of a name and an exact version. It also defines
  -- a 'Dependency' data type. A dependency is a package name and a version
  -- range, like @\"foo >= 1.2 && < 2\"@.
  
  {- All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  
      * Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials provided
        with the distribution.
  
      * Neither the name of Isaac Jones nor the names of other
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  module Distribution.Package (
          -- * Package ids
          PackageName(..),
          PackageIdentifier(..),
          PackageId,
  
          -- * Installed package identifiers
          InstalledPackageId(..),
  
          -- * Package source dependencies
          Dependency(..),
          thisPackageVersion,
          notThisPackageVersion,
          simplifyDependency,
  
          -- * Package classes
          Package(..), packageName, packageVersion,
          PackageFixedDeps(..),
    ) where
  
  import Distribution.Version
           ( Version(..), VersionRange, anyVersion, thisVersion
           , notThisVersion, simplifyVersionRange )
  
  import Distribution.Text (Text(..))
  import qualified Distribution.Compat.ReadP as Parse
  import Distribution.Compat.ReadP ((<++))
  import qualified Text.PrettyPrint as Disp
  import Text.PrettyPrint ((<>), (<+>), text)
  import qualified Data.Char as Char ( isDigit, isAlphaNum )
  import Data.List ( intersperse )
  
  newtype PackageName = PackageName String
      deriving (Read, Show, Eq, Ord)
  
  instance Text PackageName where
    disp (PackageName n) = Disp.text n
    parse = do
      ns <- Parse.sepBy1 component (Parse.char '-')
      return (PackageName (concat (intersperse "-" ns)))
      where
        component = do
          cs <- Parse.munch1 Char.isAlphaNum
          if all Char.isDigit cs then Parse.pfail else return cs
          -- each component must contain an alphabetic character, to avoid
          -- ambiguity in identifiers like foo-1 (the 1 is the version number).
  
  -- | Type alias so we can use the shorter name PackageId.
  type PackageId = PackageIdentifier
  
  -- | The name and version of a package.
  data PackageIdentifier
      = PackageIdentifier {
          pkgName    :: PackageName, -- ^The name of this package, eg. foo
          pkgVersion :: Version -- ^the version of this package, eg 1.2
       }
       deriving (Read, Show, Eq, Ord)
  
  instance Text PackageIdentifier where
    disp (PackageIdentifier n v) = case v of
      Version [] _ -> disp n -- if no version, don't show version.
      _            -> disp n <> Disp.char '-' <> disp v
  
    parse = do
      n <- parse
      v <- (Parse.char '-' >> parse) <++ return (Version [] [])
      return (PackageIdentifier n v)
  
  -- ------------------------------------------------------------
  -- * Installed Package Ids
  -- ------------------------------------------------------------
  
  -- | An InstalledPackageId uniquely identifies an instance of an installed package.
  -- There can be at most one package with a given 'InstalledPackageId'
  -- in a package database, or overlay of databases.
  --
  newtype InstalledPackageId = InstalledPackageId String
   deriving (Read,Show,Eq,Ord)
  
  instance Text InstalledPackageId where
    disp (InstalledPackageId str) = text str
  
    parse = InstalledPackageId `fmap` Parse.munch1 abi_char
     where abi_char c = Char.isAlphaNum c || c `elem` ":-_."
  
  -- ------------------------------------------------------------
  -- * Package source dependencies
  -- ------------------------------------------------------------
  
  -- | Describes a dependency on a source package (API)
  --
  data Dependency = Dependency PackageName VersionRange
                    deriving (Read, Show, Eq)
  
  instance Text Dependency where
    disp (Dependency name ver) =
      disp name <+> disp ver
  
    parse = do name <- parse
               Parse.skipSpaces
               ver <- parse <++ return anyVersion
               Parse.skipSpaces
               return (Dependency name ver)
  
  thisPackageVersion :: PackageIdentifier -> Dependency
  thisPackageVersion (PackageIdentifier n v) =
    Dependency n (thisVersion v)
  
  notThisPackageVersion :: PackageIdentifier -> Dependency
  notThisPackageVersion (PackageIdentifier n v) =
    Dependency n (notThisVersion v)
  
  -- | Simplify the 'VersionRange' expression in a 'Dependency'.
  -- See 'simplifyVersionRange'.
  --
  simplifyDependency :: Dependency -> Dependency
  simplifyDependency (Dependency name range) =
    Dependency name (simplifyVersionRange range)
  
  -- | Class of things that have a 'PackageIdentifier'
  --
  -- Types in this class are all notions of a package. This allows us to have
  -- different types for the different phases that packages go though, from
  -- simple name\/id, package description, configured or installed packages.
  --
  -- Not all kinds of packages can be uniquely identified by a
  -- 'PackageIdentifier'. In particular, installed packages cannot, there may be
  -- many installed instances of the same source package.
  --
  class Package pkg where
    packageId :: pkg -> PackageIdentifier
  
  packageName    :: Package pkg => pkg -> PackageName
  packageName     = pkgName    . packageId
  
  packageVersion :: Package pkg => pkg -> Version
  packageVersion  = pkgVersion . packageId
  
  instance Package PackageIdentifier where
    packageId = id
  
  -- | Subclass of packages that have specific versioned dependencies.
  --
  -- So for example a not-yet-configured package has dependencies on version
  -- ranges, not specific versions. A configured or an already installed package
  -- depends on exact versions. Some operations or data structures (like
  --  dependency graphs) only make sense on this subclass of package types.
  --
  class Package pkg => PackageFixedDeps pkg where
    depends :: pkg -> [PackageIdentifier]
  