Cabal-1.8.0.2: A framework for packaging Haskell softwareContentsIndex
Distribution.Version
Portabilityportable
Maintainercabal-devel@haskell.org
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
Version
data VersionRange
= AnyVersion
| ThisVersion Version
| LaterVersion Version
| EarlierVersion Version
| WildcardVersion Version
| UnionVersionRanges VersionRange VersionRange
| IntersectVersionRanges VersionRange 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) -> 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
Version
Version ranges
data VersionRange
Constructors
AnyVersion
ThisVersion Version
LaterVersion Version
EarlierVersion Version
WildcardVersion Version
UnionVersionRanges VersionRange VersionRange
IntersectVersionRanges VersionRange VersionRange
show/hide Instances
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
::
=> 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'
::
=> 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
-> 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
show/hide Instances
data UpperBound
Constructors
NoUpperBound
UpperBound Version !Bound
show/hide Instances
data Bound
Constructors
ExclusiveBound
InclusiveBound
show/hide 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 VersionIntervals.
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 VersionRanges. 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.

show/hide Instances
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
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