Copyright  (c) The University of Glasgow 2004 

License  BSDstyle (see the file libraries/base/LICENSE) 
Maintainer  [email protected] 
Stability  experimental 
Portability  nonportable (local universal quantification in ReadP) 
Safe Haskell  Safe 
Language  Haskell2010 
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.
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 prereleases 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.
Version  
Fields

IsList Version  Since: base4.8.0.0 
Eq Version  Since: base2.1 
Data Version  Since: base4.7.0.0 
Defined in Data.Data Methodsgfoldl :: (forall d b. Data d => c (d > b) > d > c b) > (forall g. g > c g) > Version > c Version Source gunfold :: (forall b r. Data b => c (b > r) > c r) > (forall r. r > c r) > Constr > c Version Source toConstr :: Version > Constr Source dataTypeOf :: Version > DataType Source dataCast1 :: Typeable t => (forall d. Data d => c (t d)) > Maybe (c Version) Source dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) > Maybe (c Version) Source gmapT :: (forall b. Data b => b > b) > Version > Version Source gmapQl :: (r > r' > r) > r > (forall d. Data d => d > r') > Version > r Source gmapQr :: (r' > r > r) > r > (forall d. Data d => d > r') > Version > r Source gmapQ :: (forall d. Data d => d > u) > Version > [u] Source gmapQi :: Int > (forall d. Data d => d > u) > Version > u Source gmapM :: Monad m => (forall d. Data d => d > m d) > Version > m Version Source gmapMp :: MonadPlus m => (forall d. Data d => d > m d) > Version > m Version Source gmapMo :: MonadPlus m => (forall d. Data d => d > m d) > Version > m Version Source  
Ord Version  Since: base2.1 
Read Version  Since: base2.1 
Show Version  Since: base2.1 
Generic Version  
type Rep Version  Since: base4.9.0.0 
Defined in Data.Version type Rep Version = D1 (MetaData "Version" "Data.Version" "base" False) (C1 (MetaCons "Version" PrefixI True) (S1 (MetaSel (Just "versionBranch") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [Int]) :*: S1 (MetaSel (Just "versionTags") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [String])))  
type Item Version  
showVersion :: Version > String Source
Provides one possible concrete representation for Version
. For a version with versionBranch
= [1,2,3]
and versionTags
= ["tag1","tag2"]
, the output will be 1.2.3tag1tag2
.
parseVersion :: ReadP Version Source
A parser for versions in the format produced by showVersion
.
makeVersion :: [Int] > Version Source
Construct tagless Version
Since: base4.8.0.0
© The University of Glasgow and others
Licensed under a BSDstyle license (see top of the page).
https://downloads.haskell.org/~ghc/8.6.1/docs/html/libraries/base4.12.0.0/DataVersion.html