| Portability | portable |
|---|---|
| Maintainer | cabal-devel@haskell.org |
| Safe Haskell | Safe-Inferred |
Distribution.Package
Description
Defines a package identifier along with a parser and pretty printer for it.
PackageIdentifiers consist of a name and an exact version. It also defines
a Dependency data type. A dependency is a package name and a version
range, like "foo >= 1.2 && < 2".
- newtype PackageName = PackageName String
- data PackageIdentifier = PackageIdentifier {}
- type PackageId = PackageIdentifier
- newtype InstalledPackageId = InstalledPackageId String
- data Dependency = Dependency PackageName VersionRange
- thisPackageVersion :: PackageIdentifier -> Dependency
- notThisPackageVersion :: PackageIdentifier -> Dependency
- simplifyDependency :: Dependency -> Dependency
- class Package pkg where
- packageId :: pkg -> PackageIdentifier
- packageName :: Package pkg => pkg -> PackageName
- packageVersion :: Package pkg => pkg -> Version
- class Package pkg => PackageFixedDeps pkg where
- depends :: pkg -> [PackageIdentifier]
Package ids
newtype PackageName
Constructors
| PackageName String |
data PackageIdentifier
The name and version of a package.
Constructors
| PackageIdentifier | |
Fields
| |
type PackageId = PackageIdentifier
Type alias so we can use the shorter name PackageId.
Installed package identifiers
newtype InstalledPackageId
An InstalledPackageId uniquely identifies an instance of an installed
package. There can be at most one package with a given InstalledPackageId
in a package database, or overlay of databases.
Constructors
| InstalledPackageId String |
Package source dependencies
data Dependency
Describes a dependency on a source package (API)
Constructors
| Dependency PackageName VersionRange |
simplifyDependency :: Dependency -> Dependency
Simplify the VersionRange expression in a Dependency.
See simplifyVersionRange.
Package classes
class Package pkg where
Class of things that have a PackageIdentifier
Types in this class are all notions of a package. This allows us to have different types for the different phases that packages go though, from simple name/id, package description, configured or installed packages.
Not all kinds of packages can be uniquely identified by a
PackageIdentifier. In particular, installed packages cannot, there may be
many installed instances of the same source package.
Methods
packageId :: pkg -> PackageIdentifier
packageName :: Package pkg => pkg -> PackageName
packageVersion :: Package pkg => pkg -> Version
class Package pkg => PackageFixedDeps pkg where
Subclass of packages that have specific versioned dependencies.
So for example a not-yet-configured package has dependencies on version ranges, not specific versions. A configured or an already installed package depends on exact versions. Some operations or data structures (like dependency graphs) only make sense on this subclass of package types.
Methods
depends :: pkg -> [PackageIdentifier]