Copyright  (c) The University of Glasgow 2004 

License  BSDstyle (see the file libraries/base/LICENSE) 
Maintainer  libraries@haskell.org 
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.
Synopsis
 data Version = Version {
 versionBranch :: [Int]
 versionTags :: [String]
 showVersion :: Version > String
 parseVersion :: ReadP Version
 makeVersion :: [Int] > Version
The Version
type
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  

Instances
IsList Version #  Since: base4.8.0.0 
Eq Version #  Since: base2.1 
Data Version #  Since: base4.7.0.0 
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d > b) > d > c b) > (forall g. g > c g) > Version > c Version # gunfold :: (forall b r. Data b => c (b > r) > c r) > (forall r. r > c r) > Constr > c Version # toConstr :: Version > Constr # dataTypeOf :: Version > DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) > Maybe (c Version) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) > Maybe (c Version) # gmapT :: (forall b. Data b => b > b) > Version > Version # gmapQl :: (r > r' > r) > r > (forall d. Data d => d > r') > Version > r # gmapQr :: forall r r'. (r' > r > r) > r > (forall d. Data d => d > r') > Version > r # gmapQ :: (forall d. Data d => d > u) > Version > [u] # gmapQi :: Int > (forall d. Data d => d > u) > Version > u # gmapM :: Monad m => (forall d. Data d => d > m d) > Version > m Version # gmapMp :: MonadPlus m => (forall d. Data d => d > m d) > Version > m Version # gmapMo :: MonadPlus m => (forall d. Data d => d > m d) > Version > m Version #  
Ord Version #  Since: base2.1 
Read Version #  Since: base2.1 
Show Version #  Since: base2.1 
Generic Version #  Since: base4.9.0.0 
type Rep Version #  
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 #  
A concrete representation of Version
showVersion :: Version > String #
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 #
A parser for versions in the format produced by showVersion
.
Constructor function
makeVersion :: [Int] > Version #
Construct tagless Version
Since: base4.8.0.0