{-# 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]
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
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. 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 forall a. Eq a => a -> a -> Bool
== Version -> [Int]
versionBranch Version
v2
                Bool -> Bool -> Bool
&& forall a. Ord a => [a] -> [a]
sort (Version -> [String]
versionTags Version
v1) forall a. Eq a => a -> a -> Bool
== 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 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)
  = forall (t :: * -> *) a. Foldable t => t [a] -> [a]
concat (forall a. a -> [a] -> [a]
intersperse String
"." (forall a b. (a -> b) -> [a] -> [b]
map forall a. Show a => a -> String
show [Int]
branch)) forall a. [a] -> [a] -> [a]
++
     forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap (Char
'-'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 <- forall a sep. ReadP a -> ReadP sep -> ReadP [a]
sepBy1 (forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap forall a. Read a => String -> a
read ((Char -> Bool) -> ReadP String
munch1 Char -> Bool
isDigit)) (Char -> ReadP Char
char Char
'.')
                  [String]
tags   <- forall a. ReadP a -> ReadP [a]
many (Char -> ReadP Char
char Char
'-' forall (f :: * -> *) a b. Applicative f => f a -> f b -> f b
*> (Char -> Bool) -> ReadP String
munch1 Char -> Bool
isAlphaNum)
                  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 []