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GHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05

Moduleghc-9.10.3GHC2021

GHC.Unit.Info

Info about installed units (compiled libraries)

  • 8 types
  • 13 values
  • Packageghc-9.10.3
  • Exports21
  • LanguageGHC2021
  • LicenceBSD-3-Clause
  • SourceInfo.hs
datadata GenericUnitInfo srcpkgid srcpkgname uid modulename mod
#

Information about an unit (a unit is an installed module library).

This is a subset of Cabal's InstalledPackageInfo, with just the bits that GHC is interested in.

Some types are left as parameters to be instantiated differently in ghc-pkg and in ghc itself.

Constructors

  • GenericUnitInfo
    • unitId :: uid

      Unique unit identifier that is used during compilation (e.g. to generate symbols).

    • unitInstanceOf :: uid

      Identifier of an indefinite unit (i.e. with module holes) that this unit is an instance of.

      For non instantiated units, unitInstanceOf=unitId

    • unitInstantiations :: [(modulename, mod)]

      How this unit instantiates some of its module holes. Map hole module names to actual module

    • unitPackageId :: srcpkgid

      Source package identifier.

      Cabal instantiates this with Distribution.Types.PackageId.PackageId type which only contains the source package name and version. Notice that it doesn't contain the Hackage revision, nor any kind of hash.

    • unitPackageName :: srcpkgname

      Source package name

    • unitPackageVersion :: Version

      Source package version

    • unitComponentName :: Maybe srcpkgname

      Name of the component.

      Cabal supports more than one components (libraries, executables, testsuites) in the same package. Each component has a name except the default one (that can only be a library component) for which we use Nothing.

      GHC only deals with "library" components as they are the only kind of components that can be registered in a database and used by other modules.

    • unitAbiHash :: ShortText

      ABI hash used to avoid mixing up units compiled with different dependencies, compiler, options, etc.

    • unitDepends :: [uid]

      Identifiers of the units this one depends on

    • unitAbiDepends :: [(uid, ShortText)]

      Like unitDepends, but each dependency is annotated with the ABI hash we expect the dependency to respect.

    • unitImportDirs :: [FilePathST]

      Directories containing module interfaces

    • unitLibraries :: [ShortText]

      Names of the Haskell libraries provided by this unit

    • unitExtDepLibsSys :: [ShortText]

      Names of the external system libraries that this unit depends on. See also unitExtDepLibsGhc field.

    • unitExtDepLibsGhc :: [ShortText]

      Because of slight differences between the GHC dynamic linker (in GHC.Runtime.Linker) and the native system linker, some packages have to link with a different list of libraries when using GHC's. Examples include: libs that are actually gnu ld scripts, and the possibility that the .a libs do not exactly match the .so/.dll equivalents.

      If this field is set, then we use that instead of the unitExtDepLibsSys field.

    • unitLibraryDirs :: [FilePathST]

      Directories containing libraries provided by this unit. See also unitLibraryDynDirs.

      It seems to be used to store paths to external library dependencies too.

    • unitLibraryDynDirs :: [FilePathST]

      Directories containing the dynamic libraries provided by this unit. See also unitLibraryDirs.

      It seems to be used to store paths to external dynamic library dependencies too.

    • unitExtDepFrameworks :: [ShortText]

      Names of the external MacOS frameworks that this unit depends on.

    • unitExtDepFrameworkDirs :: [FilePathST]

      Directories containing MacOS frameworks that this unit depends on.

    • unitLinkerOptions :: [ShortText]

      Linker (e.g. ld) command line options

    • unitCcOptions :: [ShortText]

      C compiler options that needs to be passed to the C compiler when we compile some C code against this unit.

    • unitIncludes :: [ShortText]

      C header files that are required by this unit (provided by this unit or external)

    • unitIncludeDirs :: [FilePathST]

      Directories containing C header files that this unit depends on.

    • unitHaddockInterfaces :: [FilePathST]

      Paths to Haddock interface files for this unit

    • unitHaddockHTMLs :: [FilePathST]

      Paths to Haddock directories containing HTML files

    • unitExposedModules :: [(modulename, Maybe mod)]

      Modules exposed by the unit.

      A module can be re-exported from another package. In this case, we indicate the module origin in the second parameter.

    • unitHiddenModules :: [modulename]

      Hidden modules.

      These are useful for error reporting (e.g. if a hidden module is imported)

    • unitIsIndefinite :: Bool

      True if this unit has some module holes that need to be instantiated with real modules to make the unit usable (a.k.a. Backpack).

    • unitIsExposed :: Bool

      True if the unit is exposed. A unit could be installed in a database by "disabled" by not being exposed.

    • unitIsTrusted :: Bool

      True if the unit is trusted (cf Safe Haskell)

Instances3Binary, Eq, Show
  • Binary DbUnitInfoDefined in ghc-boot-9.10.3 · GHC.Unit.Database
  • (Eq uid, Eq modulename, Eq mod, Eq srcpkgid, Eq srcpkgname) => Eq (GenericUnitInfo srcpkgid srcpkgname uid modulename mod)Defined in ghc-boot-9.10.3 · GHC.Unit.Database
  • (Show uid, Show modulename, Show mod, Show srcpkgid, Show srcpkgname) => Show (GenericUnitInfo srcpkgid srcpkgname uid modulename mod)Defined in ghc-boot-9.10.3 · GHC.Unit.Database
datadata Version
#

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
    • 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.

Instances11IsList, Eq, Data, Ord, Read, Show, …