data Version Source

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.

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 1.2.3-tag1-tag2.

parseVersion :: ReadP Version Source

A parser for versions in the format produced by showVersion.

makeVersion :: [Int] -> Version Source

Construct tag-less Version

Since: base-4.8.0.0