    {-# LANGUAGE Safe #-}
    {-# LANGUAGE DeriveGeneric #-}
    {-# LANGUAGE NoImplicitPrelude #-}

    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Data.Version
    -- Copyright   :  (c) The University of Glasgow 2004
    -- License     :  BSD-style (see the file libraries/base/LICENSE)
    --
    -- Maintainer  :  libraries@haskell.org
    -- Stability   :  experimental
    -- Portability :  non-portable (local universal quantification in ReadP)
    --
    -- A general library for representation and manipulation of versions.
    --
    -- Versioning schemes are many and varied, so the version
    -- representation provided by this library is intended to be a
    -- compromise between complete generality, where almost no common
    -- functionality could reasonably be provided, and fixing a particular
    -- versioning scheme, which would probably be too restrictive.
    --
    -- So the approach taken here is to provide a representation which
    -- subsumes many of the versioning schemes commonly in use, and we
    -- provide implementations of 'Eq', 'Ord' and conversion to\/from 'String'
    -- which will be appropriate for some applications, but not all.
    --
    -----------------------------------------------------------------------------

    module Data.Version (
            -- * The @Version@ type
            Version(..),
            -- * A concrete representation of @Version@
            showVersion, parseVersion,
            -- * Constructor function
            makeVersion
      ) where

    import Data.Functor     ( Functor(..) )
    import Control.Applicative ( Applicative(..) )
    import Data.Bool        ( (&&) )
    import Data.Char        ( isDigit, isAlphaNum )
    import Data.Eq
    import Data.Int         ( Int )
    import Data.List        ( map, sort, concat, concatMap, intersperse, (++) )
    import Data.Ord
    import Data.String      ( String )
    import GHC.Generics
    import GHC.Read
    import GHC.Show
    import Text.ParserCombinators.ReadP
    import Text.Read        ( read )

    {- |
    A 'Version' represents the version of a software entity.

    An instance of 'Eq' is provided, which implements exact equality
    modulo reordering of the tags in the 'versionTags' field.

    An instance of 'Ord' is also provided, which gives lexicographic
    ordering on the 'versionBranch' fields (i.e. 2.1 > 2.0, 1.2.3 > 1.2.2,
    etc.).  This is expected to be sufficient for many uses, but note that
    you may need to use a more specific ordering for your versioning
    scheme.  For example, some versioning schemes may include pre-releases
    which have tags @\"pre1\"@, @\"pre2\"@, and so on, and these would need to
    be taken into account when determining ordering.  In some cases, date
    ordering may be more appropriate, so the application would have to
    look for @date@ tags in the 'versionTags' field and compare those.
    The bottom line is, don't always assume that 'compare' and other 'Ord'
    operations are the right thing for every 'Version'.

    Similarly, concrete representations of versions may differ.  One
    possible concrete representation is provided (see 'showVersion' and
    'parseVersion'), but depending on the application a different concrete
    representation may be more appropriate.
    -}
    data Version =
      Version { Version -> [Int]
    versionBranch :: [Int],
                    -- ^ The numeric branch for this version.  This reflects the
                    -- fact that most software versions are tree-structured; there
                    -- is a main trunk which is tagged with versions at various
                    -- points (1,2,3...), and the first branch off the trunk after
                    -- version 3 is 3.1, the second branch off the trunk after
                    -- version 3 is 3.2, and so on.  The tree can be branched
                    -- arbitrarily, just by adding more digits.
                    --
                    -- We represent the branch as a list of 'Int', so
                    -- version 3.2.1 becomes [3,2,1].  Lexicographic ordering
                    -- (i.e. the default instance of 'Ord' for @[Int]@) gives
                    -- the natural ordering of branches.

               Version -> [String]
    versionTags :: [String]  -- really a bag
                    -- ^ A version can be tagged with an arbitrary list of strings.
                    -- The interpretation of the list of tags is entirely dependent
                    -- on the entity that this version applies to.
            }
      deriving ( ReadPrec [Version]
    ReadPrec Version
    Int -> ReadS Version
    ReadS [Version]
    (Int -> ReadS Version)
    -> ReadS [Version]
    -> ReadPrec Version
    -> ReadPrec [Version]
    -> Read Version
    forall a.
    (Int -> ReadS a)
    -> ReadS [a] -> ReadPrec a -> ReadPrec [a] -> Read a
    readListPrec :: ReadPrec [Version]
    $creadListPrec :: ReadPrec [Version]
    readPrec :: ReadPrec Version
    $creadPrec :: ReadPrec Version
    readList :: ReadS [Version]
    $creadList :: ReadS [Version]
    readsPrec :: Int -> ReadS Version
    $creadsPrec :: Int -> ReadS Version
    Read    -- ^ @since 2.01
               , Int -> Version -> ShowS
    [Version] -> ShowS
    Version -> String
    (Int -> Version -> ShowS)
    -> (Version -> String) -> ([Version] -> ShowS) -> Show Version
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    showList :: [Version] -> ShowS
    $cshowList :: [Version] -> ShowS
    show :: Version -> String
    $cshow :: Version -> String
    showsPrec :: Int -> Version -> ShowS
    $cshowsPrec :: Int -> Version -> ShowS
    Show    -- ^ @since 2.01
               , (forall x. Version -> Rep Version x)
    -> (forall x. Rep Version x -> Version) -> Generic Version
    forall x. Rep Version x -> Version
    forall x. Version -> Rep Version x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cto :: forall x. Rep Version x -> Version
    $cfrom :: forall x. Version -> Rep Version x
    Generic -- ^ @since 4.9.0.0
               )
    {-# DEPRECATED versionTags "See GHC ticket #2496" #-}
    -- TODO. Remove all references to versionTags in GHC 8.0 release.

    -- | @since 2.01
    instance Eq Version where
      Version
    v1 == :: Version -> Version -> Bool
    == Version
    v2  =  Version -> [Int]
    versionBranch Version
    v1 [Int] -> [Int] -> Bool
    forall a. Eq a => a -> a -> Bool
    == Version -> [Int]
    versionBranch Version
    v2
                    Bool -> Bool -> Bool
    && [String] -> [String]
    forall a. Ord a => [a] -> [a]
    sort (Version -> [String]
    versionTags Version
    v1) [String] -> [String] -> Bool
    forall a. Eq a => a -> a -> Bool
    == [String] -> [String]
    forall a. Ord a => [a] -> [a]
    sort (Version -> [String]
    versionTags Version
    v2)
                    -- tags may be in any order

    -- | @since 2.01
    instance Ord Version where
      Version
    v1 compare :: Version -> Version -> Ordering
    `compare` Version
    v2 = Version -> [Int]
    versionBranch Version
    v1 [Int] -> [Int] -> Ordering
    forall a. Ord a => a -> a -> Ordering
    `compare` Version -> [Int]
    versionBranch Version
    v2

    -- -----------------------------------------------------------------------------
    -- A concrete representation of 'Version'

    -- | Provides one possible concrete representation for 'Version'.  For
    -- a version with 'versionBranch' @= [1,2,3]@ and 'versionTags'
    -- @= [\"tag1\",\"tag2\"]@, the output will be @1.2.3-tag1-tag2@.
    --
    showVersion :: Version -> String
    showVersion :: Version -> String
    showVersion (Version [Int]
    branch [String]
    tags)
      = [String] -> String
    forall (t :: * -> *) a. Foldable t => t [a] -> [a]
    concat (String -> [String] -> [String]
    forall a. a -> [a] -> [a]
    intersperse String
    "." ((Int -> String) -> [Int] -> [String]
    forall a b. (a -> b) -> [a] -> [b]
    map Int -> String
    forall a. Show a => a -> String
    show [Int]
    branch)) String -> ShowS
    forall a. [a] -> [a] -> [a]
    ++
         ShowS -> [String] -> String
    forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
    concatMap (Char
    '-'Char -> ShowS
    forall a. a -> [a] -> [a]
    :) [String]
    tags

    -- | A parser for versions in the format produced by 'showVersion'.
    --
    parseVersion :: ReadP Version
    parseVersion :: ReadP Version
    parseVersion = do [Int]
    branch <- ReadP Int -> ReadP Char -> ReadP [Int]
    forall a sep. ReadP a -> ReadP sep -> ReadP [a]
    sepBy1 ((String -> Int) -> ReadP String -> ReadP Int
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap String -> Int
    forall a. Read a => String -> a
    read ((Char -> Bool) -> ReadP String
    munch1 Char -> Bool
    isDigit)) (Char -> ReadP Char
    char Char
    '.')
                      [String]
    tags   <- ReadP String -> ReadP [String]
    forall a. ReadP a -> ReadP [a]
    many (Char -> ReadP Char
    char Char
    '-' ReadP Char -> ReadP String -> ReadP String
    forall (f :: * -> *) a b. Applicative f => f a -> f b -> f b
    *> (Char -> Bool) -> ReadP String
    munch1 Char -> Bool
    isAlphaNum)
                      Version -> ReadP Version
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure Version{versionBranch :: [Int]
    versionBranch=[Int]
    branch, versionTags :: [String]
    versionTags=[String]
    tags}

    -- | Construct tag-less 'Version'
    --
    -- @since 4.8.0.0
    makeVersion :: [Int] -> Version
    makeVersion :: [Int] -> Version
    makeVersion [Int]
    b = [Int] -> [String] -> Version
    Version [Int]
    b []