Distribution.Types.VersionInterval

This module implements a view of a VersionRange as a finite list of separated version intervals.

In conversion from and to VersionRange it makes some effort to preserve the caret operator ^>=x.y. This constraint a priori specifies the same interval as ==x.y.*, but indicates that newer versions could be acceptable (allow-newer: ^).

Version intervals

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.

Instances

Show VersionIntervals

Defined in Distribution.Types.VersionInterval

Methods

showsPrec :: Int -> VersionIntervals -> ShowS

show :: VersionIntervals -> String

showList :: [VersionIntervals] -> ShowS

Eq VersionIntervals

Defined in Distribution.Types.VersionInterval

Methods

(==) :: VersionIntervals -> VersionIntervals -> Bool

(/=) :: VersionIntervals -> VersionIntervals -> Bool

unVersionIntervals :: VersionIntervals -> [VersionInterval]

Inspect the list of version intervals.

mkVersionIntervals :: [VersionInterval] -> Maybe VersionIntervals

Directly construct a VersionIntervals from a list of intervals.

Conversions

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.

Normalisation

normaliseVersionRange2 :: VersionRange -> VersionRange

Since Cabal-3.6 this function.. TODO

Relaxation

relaxLastInterval :: VersionIntervals -> VersionIntervals

relaxHeadInterval :: VersionIntervals -> VersionIntervals

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 && 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

data VersionInterval

Constructors

VersionInterval !LowerBound !UpperBound

Instances

Show VersionInterval

Defined in Distribution.Types.VersionInterval

Methods

showsPrec :: Int -> VersionInterval -> ShowS

show :: VersionInterval -> String

showList :: [VersionInterval] -> ShowS

Eq VersionInterval

Defined in Distribution.Types.VersionInterval

Methods

(==) :: VersionInterval -> VersionInterval -> Bool

(/=) :: VersionInterval -> VersionInterval -> Bool

data LowerBound

Constructors

LowerBound !Version !Bound

Instances

Show LowerBound

Defined in Distribution.Types.VersionInterval

Methods

showsPrec :: Int -> LowerBound -> ShowS

show :: LowerBound -> String

showList :: [LowerBound] -> ShowS

Eq LowerBound

Defined in Distribution.Types.VersionInterval

Methods

(==) :: LowerBound -> LowerBound -> Bool

(/=) :: LowerBound -> LowerBound -> Bool

data UpperBound

Constructors

NoUpperBound

UpperBound !Version !Bound

Instances

Show UpperBound

Defined in Distribution.Types.VersionInterval

Methods

showsPrec :: Int -> UpperBound -> ShowS

show :: UpperBound -> String

showList :: [UpperBound] -> ShowS

Eq UpperBound

Defined in Distribution.Types.VersionInterval

Methods

(==) :: UpperBound -> UpperBound -> Bool

(/=) :: UpperBound -> UpperBound -> Bool

data Bound

Constructors

ExclusiveBound

InclusiveBound

Instances

Show Bound

Defined in Distribution.Types.VersionInterval

Methods

showsPrec :: Int -> Bound -> ShowS

show :: Bound -> String

showList :: [Bound] -> ShowS

Eq Bound

Defined in Distribution.Types.VersionInterval

Methods

(==) :: Bound -> Bound -> Bool

(/=) :: Bound -> Bound -> Bool

Invariants

invariantVersionIntervals :: VersionIntervals -> Bool

VersionIntervals invariant:

• all intervals are valid (lower bound is less then upper bound, i.e. non-empty)
• intervals doesn't touch each other (distinct)