Cabal-1.10.1.0: A framework for packaging Haskell software

Portability | portable
Maintainer | cabal-devel@haskell.org

Distribution.Version

Contents

- Package versions
- Version ranges
  - Constructing
  - Inspection
- Version intervals view
  - `VersionIntervals` abstract type

Description

Exports the `Version` type along with a parser and pretty printer. A version is something like `"1.3.3"`. It also defines the `VersionRange` data types. Version ranges are like `">= 1.2 && < 2"`.

Synopsis

- data Version = Version {
  - versionBranch :: [Int]
  - versionTags :: [String]
  }
- data VersionRange
  - = AnyVersion
  - | ThisVersion Version
  - | LaterVersion Version
  - | EarlierVersion Version
  - | WildcardVersion Version
  - | UnionVersionRanges VersionRange VersionRange
  - | IntersectVersionRanges VersionRange VersionRange
  - | VersionRangeParens VersionRange
- anyVersion :: VersionRange
- noVersion :: VersionRange
- thisVersion :: Version -> VersionRange
- notThisVersion :: Version -> VersionRange
- laterVersion :: Version -> VersionRange
- earlierVersion :: Version -> VersionRange
- orLaterVersion :: Version -> VersionRange
- orEarlierVersion :: Version -> VersionRange
- unionVersionRanges :: VersionRange -> VersionRange -> VersionRange
- intersectVersionRanges :: VersionRange -> VersionRange -> VersionRange
- withinVersion :: Version -> VersionRange
- betweenVersionsInclusive :: Version -> Version -> VersionRange
- withinRange :: Version -> VersionRange -> Bool
- isAnyVersion :: VersionRange -> Bool
- isNoVersion :: VersionRange -> Bool
- isSpecificVersion :: VersionRange -> Maybe Version
- simplifyVersionRange :: VersionRange -> VersionRange
- foldVersionRange :: a -> (Version -> a) -> (Version -> a) -> (Version -> a) -> (a -> a -> a) -> (a -> a -> a) -> VersionRange -> a
- foldVersionRange' :: a -> (Version -> a) -> (Version -> a) -> (Version -> a) -> (Version -> a) -> (Version -> a) -> (Version -> Version -> a) -> (a -> a -> a) -> (a -> a -> a) -> (a -> a) -> VersionRange -> a
- asVersionIntervals :: VersionRange -> [VersionInterval]
- type VersionInterval = (LowerBound, UpperBound)
- data LowerBound = LowerBound Version !Bound
- data UpperBound
  - = NoUpperBound
  - | UpperBound Version !Bound
- data Bound
  - = ExclusiveBound
  - | InclusiveBound
- data VersionIntervals
- toVersionIntervals :: VersionRange -> VersionIntervals
- fromVersionIntervals :: VersionIntervals -> VersionRange
- withinIntervals :: Version -> VersionIntervals -> Bool
- versionIntervals :: VersionIntervals -> [VersionInterval]
- mkVersionIntervals :: [VersionInterval] -> Maybe VersionIntervals
- unionVersionIntervals :: VersionIntervals -> VersionIntervals -> VersionIntervals
- intersectVersionIntervals :: VersionIntervals -> VersionIntervals -> VersionIntervals

# Package versions

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.

Constructors

Version |

Fields

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.

versionTags :: [String]

  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.

Instances

Eq Version |
Ord Version |
Read Version |
Show Version |
Typeable Version |
Text Version |

# Version ranges

data VersionRange

Constructors

AnyVersion |
ThisVersion Version |
LaterVersion Version |
EarlierVersion Version |
WildcardVersion Version |
UnionVersionRanges VersionRange VersionRange |
IntersectVersionRanges VersionRange VersionRange |
VersionRangeParens VersionRange |

Instances

Eq VersionRange |
Read VersionRange |
Show VersionRange |
Text VersionRange |

## Constructing

anyVersion :: VersionRange

The version range `-any`. That is, a version range containing all versions.

     withinRange v anyVersion = True

noVersion :: VersionRange

The empty version range, that is a version range containing no versions.

This can be constructed using any unsatisfiable version range expression, for example `> 1 && < 1`.

     withinRange v anyVersion = False

thisVersion :: Version -> VersionRange

The version range `== v`

     withinRange v' (thisVersion v) = v' == v

notThisVersion :: Version -> VersionRange

The version range `v || v`

     withinRange v' (notThisVersion v) = v' /= v

laterVersion :: Version -> VersionRange

The version range `> v`

     withinRange v' (laterVersion v) = v' > v

earlierVersion :: Version -> VersionRange

The version range `< v`

     withinRange v' (earlierVersion v) = v' < v

orLaterVersion :: Version -> VersionRange

The version range `>= v`

     withinRange v' (orLaterVersion v) = v' >= v

orEarlierVersion :: Version -> VersionRange

The version range `<= v`

     withinRange v' (orEarlierVersion v) = v' <= v

unionVersionRanges :: VersionRange -> VersionRange -> VersionRange

The version range `vr1 || vr2`

       withinRange v' (unionVersionRanges vr1 vr2)
     = withinRange v' vr1 || withinRange v' vr2

intersectVersionRanges :: VersionRange -> VersionRange -> VersionRange

The version range `vr1 && vr2`

       withinRange v' (intersectVersionRanges vr1 vr2)
     = withinRange v' vr1 && withinRange v' vr2

withinVersion :: Version -> VersionRange

The version range `== v.*`.

For example, for version `1.2`, the version range `== 1.2.*` is the same as `>= 1.2 && < 1.3`

     withinRange v' (laterVersion v) = v' >= v && v' < upper v
       where
         upper (Version lower t) = Version (init lower ++ [last lower + 1]) t

betweenVersionsInclusive :: Version -> Version -> VersionRange

The version range `>= v1 && <= v2`.

In practice this is not very useful because we normally use inclusive lower bounds and exclusive upper bounds.

     withinRange v' (laterVersion v) = v' > v

## Inspection

withinRange :: Version -> VersionRange -> Bool

Does this version fall within the given range?

This is the evaluation function for the `VersionRange` type.

isAnyVersion :: VersionRange -> Bool

Does this `VersionRange` place any restriction on the `Version` or is it in fact equivalent to `AnyVersion`.

Note this is a semantic check, not simply a syntactic check. So for example the following is `True` (for all `v`).

     isAnyVersion (EarlierVersion v `UnionVersionRanges` orLaterVersion v)

isNoVersion :: VersionRange -> Bool

This is the converse of `isAnyVersion`. It check if the version range is empty, if there is no possible version that satisfies the version range.

For example this is `True` (for all `v`):

     isNoVersion (EarlierVersion v `IntersectVersionRanges` LaterVersion v)

isSpecificVersion :: VersionRange -> Maybe Version

Is this version range in fact just a specific version?

For example the version range `">= 3 && <= 3"` contains only the version `3`.

simplifyVersionRange :: VersionRange -> VersionRange

Simplify a `VersionRange` expression. For non-empty version ranges this produces a canonical form. Empty or inconsistent version ranges are left as-is because that provides more information.

If you need a canonical form use `fromVersionIntervals . toVersionIntervals`

It satisfies the following properties:

     withinRange v (simplifyVersionRange r) = withinRange v r

         withinRange v r = withinRange v r'
     ==> simplifyVersionRange r = simplifyVersionRange r'
      || isNoVersion r
      || isNoVersion r'

foldVersionRange

Arguments

:: a | `"-any"` version

-> (Version -> a)

    "== v"

-> (Version -> a)

    "> v"

-> (Version -> a)

    "< v"

-> (a -> a -> a) | `"_ || _"` union
-> (a -> a -> a) | `"_ && _"` intersection
-> VersionRange |
-> a |

Fold over the basic syntactic structure of a `VersionRange`.

This provides a syntacic view of the expression defining the version range. The syntactic sugar `">= v"`, `"<= v"` and `"== v.*"` is presented in terms of the other basic syntax.

For a semantic view use `asVersionIntervals`.

foldVersionRange'

Arguments

:: a | `"-any"` version

-> (Version -> a)

    "== v"

-> (Version -> a)

    "> v"

-> (Version -> a)

    "< v"

-> (Version -> a)

    ">= v"

-> (Version -> a)

    "<= v"

-> (Version -> Version -> a) | `"== v.*"` wildcard. The function is passed the inclusive lower bound and the exclusive upper bounds of the range defined by the wildcard.
-> (a -> a -> a) | `"_ || _"` union
-> (a -> a -> a) | `"_ && _"` intersection
-> (a -> a) | `"(_)"` parentheses
-> VersionRange |
-> a |

An extended variant of `foldVersionRange` that also provides a view of in which the syntactic sugar `">= v"`, `"<= v"` and `"== v.*"` is presented explicitly rather than in terms of the other basic syntax.

# Version intervals view

asVersionIntervals :: VersionRange -> [VersionInterval]

View a `VersionRange` as a union of intervals.

This provides a canonical view of the semantics of a `VersionRange` as opposed to the syntax of the expression used to define it. For the syntactic view use `foldVersionRange`.

Each interval is non-empty. The sequence is in increasing order and no intervals overlap or touch. Therefore only the first and last can be unbounded. The sequence can be empty if the range is empty (e.g. a range expression like `1 && 2`).

Other checks are trivial to implement using this view. For example:

     isNoVersion vr | [] <- asVersionIntervals vr = True
                    | otherwise                   = False

     isSpecificVersion vr
        | [(LowerBound v  InclusiveBound
           ,UpperBound v' InclusiveBound)] <- asVersionIntervals vr
        , v == v'   = Just v
        | otherwise = Nothing

type VersionInterval = (LowerBound, UpperBound)

data LowerBound

Constructors

LowerBound Version !Bound |

Instances

Eq LowerBound |
Ord LowerBound |
Show LowerBound |

data UpperBound

Constructors

NoUpperBound |
UpperBound Version !Bound |

Instances

Eq UpperBound |
Ord UpperBound |
Show UpperBound |

data Bound

Constructors

ExclusiveBound |
InclusiveBound |

Instances

Eq Bound |
Show Bound |

## `VersionIntervals` abstract type

The `VersionIntervals` type and the accompanying functions are exposed primarily for completeness and testing purposes. In practice `asVersionIntervals` is the main function to use to view a `VersionRange` as a bunch of `VersionInterval`s.

data VersionIntervals

A complementary representation of a `VersionRange`. Instead of a boolean version predicate it uses an increasing sequence of non-overlapping, non-empty intervals.

The key point is that this representation gives a canonical representation for the semantics of `VersionRange`s. This makes it easier to check things like whether a version range is empty, covers all versions, or requires a certain minimum or maximum version. It also makes it easy to check equality or containment. It also makes it easier to identify 'simple' version predicates for translation into foreign packaging systems that do not support complex version range expressions.

Instances

Eq VersionIntervals |
Show VersionIntervals |

toVersionIntervals :: VersionRange -> VersionIntervals

Convert a `VersionRange` to a sequence of version intervals.

fromVersionIntervals :: VersionIntervals -> VersionRange

Convert a `VersionIntervals` value back into a `VersionRange` expression representing the version intervals.

withinIntervals :: Version -> VersionIntervals -> Bool

Test if a version falls within the version intervals.

It exists mostly for completeness and testing. It satisfies the following properties:

     withinIntervals v (toVersionIntervals vr) = withinRange v vr
     withinIntervals v ivs = withinRange v (fromVersionIntervals ivs)

versionIntervals :: VersionIntervals -> [VersionInterval]

Inspect the list of version intervals.

mkVersionIntervals :: [VersionInterval] -> Maybe VersionIntervals

Directly construct a `VersionIntervals` from a list of intervals.

Each interval must be non-empty. The sequence must be in increasing order and no invervals may overlap or touch. If any of these conditions are not satisfied the function returns `Nothing`.

unionVersionIntervals :: VersionIntervals -> VersionIntervals -> VersionIntervals

intersectVersionIntervals :: VersionIntervals -> VersionIntervals -> VersionIntervals