Salve

This module defines types and functions for working with versions as defined by Semantic Versioning. It also provides types and functions for working with version constraints as described by npm.

Documentation

This module doesn't export anything that conflicts with the Prelude, so you can import it unqualified.

>>> import Salve

The Version data type is the core of this module. Use parseVersion to make versions and renderVersion to convert them into strings.

>>> renderVersion <$> parseVersion "1.2.3"
Just "1.2.3"

The Constraint data type allows you to specify version constraints. Use parseConstraint to make constraints and renderConstraint to convert them into strings.

>>> renderConstraint <$> parseConstraint ">1.2.0"
Just ">1.2.0"

Use satisfies to see if a version satisfies a constraint.

>>> satisfies <$> parseVersion "1.2.3" <*> parseConstraint ">1.2.0"
Just True

Types

data Version

A semantic version number. Versions have five parts:

1. majorLens: The major version number.
2. minorLens: The minor version number.
3. patchLens: The patch version number.
4. preReleasesLens: A list of pre-release identifiers.
5. buildsLens: A list of build metadata.

Use parseVersion to create versions.

Instances

Eq Version

Methods

(==) :: Version -> Version -> Bool

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

Ord Version

In general, Versions compare in the way that you would expect. First the major version numbers are compared, then the minors, then the patches.

>>> compare <$> parseVersion "1.2.3" <*> parseVersion "2.0.0"
Just LT
>>> compare <$> parseVersion "1.2.3" <*> parseVersion "1.3.0"
Just LT
>>> compare <$> parseVersion "1.2.3" <*> parseVersion "1.2.4"
Just LT

Numbers are compared numerically, not alphabetically.

>>> compare <$> parseVersion "0.0.9" <*> parseVersion "0.0.10"
Just LT

If all the numbers are the same, the pre-releases are compared.

>>> compare <$> parseVersion "1.2.3-a" <*> parseVersion "1.2.3-b"
Just LT

A version with a pre-release is always less than a version without one as long as the other parts are the same.

>>> compare <$> parseVersion "1.2.3-pre" <*> parseVersion "1.2.3"
Just LT
>>> compare <$> parseVersion "1.2.4-pre" <*> parseVersion "1.2.3"
Just GT

Builds are not considered when comparing versions.

>>> compare <$> parseVersion "1.2.3+a" <*> parseVersion "1.2.3+b"
Just EQ
>>> (==) <$> parseVersion "1.2.3+a" <*> parseVersion "1.2.3+b"
Just False

Methods

compare :: Version -> Version -> Ordering

(<) :: Version -> Version -> Bool

(<=) :: Version -> Version -> Bool

(>) :: Version -> Version -> Bool

(>=) :: Version -> Version -> Bool

max :: Version -> Version -> Version

min :: Version -> Version -> Version

Show Version

Methods

showsPrec :: Int -> Version -> ShowS

show :: Version -> String

showList :: [Version] -> ShowS

data PreRelease

Pre-release information attached to a version. These can either be numeric or textual. They must not be empty.

• Numeric: Can be any non-negative integer. Cannot have leading zeros.
• Textual: Can be any string of ASCII digits, letters, or hyphens. Cannot be all digits, as that would be numeric.

In general, pre-releases must match the regular expression /^[-0-9A-Za-z]+$/.

Use parsePreRelease to create pre-releases.

Instances

Eq PreRelease

Methods

(==) :: PreRelease -> PreRelease -> Bool

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

Ord PreRelease

Numeric pre-releases are always less than textual pre-releases.

>>> compare <$> parsePreRelease "1" <*> parsePreRelease "a"
Just LT

Numeric pre-releases are compared numerically.

>>> compare <$> parsePreRelease "9" <*> parsePreRelease "10"
Just LT

Textual pre-releases are compared alphabetically.

>>> compare <$> parsePreRelease "p10" <*> parsePreRelease "p9"
Just LT

Methods

compare :: PreRelease -> PreRelease -> Ordering

(<) :: PreRelease -> PreRelease -> Bool

(<=) :: PreRelease -> PreRelease -> Bool

(>) :: PreRelease -> PreRelease -> Bool

(>=) :: PreRelease -> PreRelease -> Bool

max :: PreRelease -> PreRelease -> PreRelease

min :: PreRelease -> PreRelease -> PreRelease

Show PreRelease

Methods

showsPrec :: Int -> PreRelease -> ShowS

show :: PreRelease -> String

showList :: [PreRelease] -> ShowS

data Build

Build metadata attached to a version. These are similar to PreReleases with some key differences:

1. There is no such thing as numeric builds. Even though builds can look like numbers, all builds are textual.
2. As a result, builds that look numeric are allowed to have leading zeros.
3. Builds cannot be compared. That is, they do not have an Ord instance.

Use parseBuild to create builds.

Instances

Eq Build

Methods

(==) :: Build -> Build -> Bool

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

Show Build

Methods

showsPrec :: Int -> Build -> ShowS

show :: Build -> String

showList :: [Build] -> ShowS

data Constraint

Constrains allowable version numbers.

Use parseConstraint to create constraints and satisfies to see if a version number satisfies a constraint.

Instances

Eq Constraint

Methods

(==) :: Constraint -> Constraint -> Bool

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

Show Constraint

Methods

showsPrec :: Int -> Constraint -> ShowS

show :: Constraint -> String

showList :: [Constraint] -> ShowS

Parsing

parseVersion :: String -> Maybe Version

Attempts to parse a version. This parser follows SemVer's BNF.

>>> parseVersion "1.2.3-p.4+b.5"
Just (Version {versionMajor = 1, versionMinor = 2, versionPatch = 3, versionPreReleases = [PreReleaseTextual "p",PreReleaseNumeric 4], versionBuilds = [Build "b",Build "5"]})

Returns Nothing if the parse fails.

>>> parseVersion "wrong"
Nothing

Whitespace is not allowed and will cause the parser to fail.

>>> parseVersion " 1.2.3 "
Nothing

parsePreRelease :: String -> Maybe PreRelease

Attempts to parse a pre-release.

>>> parsePreRelease "pre"
Just (PreReleaseTextual "pre")
>>> parsePreRelease "1"
Just (PreReleaseNumeric 1)

Returns Nothing if the parse fails.

>>> parsePreRelease "wrong!"
Nothing

Numeric pre-releases cannot contain leading zeros.

>>> parsePreRelease "01"
Nothing

parseBuild :: String -> Maybe Build

Attempts to parse a build.

>>> parseBuild "build"
Just (Build "build")
>>> parseBuild "1"
Just (Build "1")

Returns Nothing if the parse fails.

>>> parseBuild "wrong!"
Nothing

Unlike pre-releases, numeric builds can have leading zeros.

>>> parseBuild "01"
Just (Build "01")

parseConstraint :: String -> Maybe Constraint

Attempts to parse a constraint. This parser follows npm's BNF, except that neither the so-called "x-ranges" nor partial version numbers are not supported. So you cannot use 1.2.x or >1.2 as version constraints.

>>> parseConstraint ">1.2.3"
Just (ConstraintCompare OperatorGT (Version {versionMajor = 1, versionMinor = 2, versionPatch = 3, versionPreReleases = [], versionBuilds = []}))

Returns Nothing if the parse fails.

>>> parseConstraint "wrong"
Nothing

Unsafe

These functions can be used to unsafely parse strings. Instead of returning Nothing, they raise an exception. Only use these if you are sure the string can be successfully parsed!

unsafeParseVersion :: String -> Version

Parses a version.

>>> unsafeParseVersion "1.2.3-p.4+b.5"
Version {versionMajor = 1, versionMinor = 2, versionPatch = 3, versionPreReleases = [PreReleaseTextual "p",PreReleaseNumeric 4], versionBuilds = [Build "b",Build "5"]}

Raises an exception if the parse fails.

>>> unsafeParseVersion "wrong"
*** Exception: invalid version: "wrong"
...

See parseVersion for a safe version of this function.

unsafeParsePreRelease :: String -> PreRelease

Parses a pre-release.

>>> unsafeParsePreRelease "pre"
PreReleaseTextual "pre"

Raises an exception if the parse fails.

>>> unsafeParsePreRelease "wrong!"
*** Exception: invalid pre-release: "wrong!"
...

See parsePreRelease for a safe version of this function.

unsafeParseBuild :: String -> Build

Parses a build.

>>> unsafeParseBuild "build"
Build "build"

Raises an exception if the parse fails.

>>> unsafeParseBuild "wrong!"
Build "*** Exception: invalid build: "wrong!"
...

See parseBuild for a safe version of this function.

unsafeParseConstraint :: String -> Constraint

Parses a constraint.

>>> unsafeParseConstraint ">1.2.3"
ConstraintCompare OperatorGT (Version {versionMajor = 1, versionMinor = 2, versionPatch = 3, versionPreReleases = [], versionBuilds = []})

Raises an exception if the parse fails.

>>> unsafeParseConstraint "wrong"
*** Exception: invalid constraint: "wrong"
...

See parseConstraint for a safe version of this function.

Rendering

renderVersion :: Version -> String

Renders a version.

>>> renderVersion <$> parseVersion "1.2.3-p.4+b.5"
Just "1.2.3-p.4+b.5"

renderPreRelease :: PreRelease -> String

Renders a pre-release.

>>> renderPreRelease <$> parsePreRelease "pre"
Just "pre"
>>> renderPreRelease <$> parsePreRelease "1"
Just "1"

renderBuild :: Build -> String

Renders a build.

>>> renderBuild <$> parseBuild "build"
Just "build"
>>> renderBuild <$> parseBuild "1"
Just "1"

renderConstraint :: Constraint -> String

Renders a constraint.

>>> renderConstraint <$> parseConstraint ">1.2.3"
Just ">1.2.3"

Parsing and rendering a constraint doesn't always return what you started with.

>>> renderConstraint <$> parseConstraint "=1.2.3"
Just "1.2.3"

Predicates

isUnstable :: Version -> Bool

Returns True if the major version number is zero, False otherwise.

>>> isUnstable <$> parseVersion "0.1.2"
Just True
>>> isUnstable <$> parseVersion "1.0.0"
Just False

isStable :: Version -> Bool

Returns True if the major version number is not zero, False otherwise.

>>> isStable <$> parseVersion "1.0.0"
Just True
>>> isStable <$> parseVersion "0.1.2"
Just False

Helpers

bumpMajor :: Version -> Version

Increments the major version number.

>>> bumpMajor <$> parseVersion "0.0.0"
Just (Version {versionMajor = 1, versionMinor = 0, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

The minor and patch numbers are reset to zero.

>>> bumpMajor <$> parseVersion "1.2.3"
Just (Version {versionMajor = 2, versionMinor = 0, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

The pre-releases and builds are removed.

>>> bumpMajor <$> parseVersion "0.0.0-pre+build"
Just (Version {versionMajor = 1, versionMinor = 0, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

Consider using majorLens if you want to arbitrarily change the major number, or if you don't want the other parts of the version to change.

bumpMinor :: Version -> Version

Increments the minor version number.

>>> bumpMinor <$> parseVersion "0.0.0"
Just (Version {versionMajor = 0, versionMinor = 1, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

The patch number is reset to zero.

>>> bumpMinor <$> parseVersion "1.2.3"
Just (Version {versionMajor = 1, versionMinor = 3, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

The pre-releases and builds are removed.

>>> bumpMinor <$> parseVersion "0.0.0-pre+build"
Just (Version {versionMajor = 0, versionMinor = 1, versionPatch = 0, versionPreReleases = [], versionBuilds = []})

Consider using minorLens if you want to arbitrarily change the minor number, or if you don't want the other parts of the version to change.

bumpPatch :: Version -> Version

Increments the patch number.

>>> bumpPatch <$> parseVersion "0.0.0"
Just (Version {versionMajor = 0, versionMinor = 0, versionPatch = 1, versionPreReleases = [], versionBuilds = []})

The major and minor numbers are not changed.

>>> bumpPatch <$> parseVersion "1.2.3"
Just (Version {versionMajor = 1, versionMinor = 2, versionPatch = 4, versionPreReleases = [], versionBuilds = []})

The pre-releases and builds are removed.

>>> bumpPatch <$> parseVersion "0.0.0-pre+build"
Just (Version {versionMajor = 0, versionMinor = 0, versionPatch = 1, versionPreReleases = [], versionBuilds = []})

Consider using patchLens if you want to arbitrarily change the patch number, or if you don't want the other parts of the version to change.

satisfies :: Version -> Constraint -> Bool

Returns True if the version satisfies the constraint, False otherwise.

>>> satisfies <$> parseVersion "1.2.3" <*> parseConstraint ">1.2.0"
Just True

Lenses

These lenses can be used to access and modify specific parts of a Version.

Don't be scared by these type signatures. They are provided in full to avoid the RankNTypes language extension. The type signature Functor f => (a -> f a) -> Version -> f Version is the same as Lens' Version a (from Lens.Micro), which you may already be familiar with.

majorLens :: Functor f => (Word -> f Word) -> Version -> f Version

Focuses on the major version number.

>>> view majorLens <$> parseVersion "1.2.3-pre.4+build.5"
Just 1

minorLens :: Functor f => (Word -> f Word) -> Version -> f Version

Focuses on the minor version number.

>>> view minorLens <$> parseVersion "1.2.3-pre.4+build.5"
Just 2

patchLens :: Functor f => (Word -> f Word) -> Version -> f Version

Focuses on the patch version number.

>>> view patchLens <$> parseVersion "1.2.3-pre.4+build.5"
Just 3

preReleasesLens :: Functor f => ([PreRelease] -> f [PreRelease]) -> Version -> f Version

Focuses on the pre-release identifiers.

>>> view preReleasesLens <$> parseVersion "1.2.3-pre.4+build.5"
Just [PreReleaseTextual "pre",PreReleaseNumeric 4]

buildsLens :: Functor f => ([Build] -> f [Build]) -> Version -> f Version

Focuses on the build metadata.

>>> view buildsLens <$> parseVersion "1.2.3-pre.4+build.5"
Just [Build "build",Build "5"]