Safe Haskell	None
Language	Haskell2010

Packages

Contents

Reading the package config, and processing cmdline args
Querying the package config
Inspecting the set of packages in scope
Utils

Description

Package manipulation

Synopsis

Documentation

module PackageConfig

Reading the package config, and processing cmdline args

data PackageState Source

initPackages :: DynFlags -> IO (DynFlags, [PackageKey]) Source

Call this after parseDynFlags. It reads the package database files, and sets up various internal tables of package information, according to the package-related flags on the command-line (-package, -hide-package etc.)

Returns a list of packages to link in if we're doing dynamic linking. This list contains the packages that the user explicitly mentioned with -package flags.

initPackages can be called again subsequently after updating the packageFlags field of the DynFlags, and it will update the pkgState in DynFlags and return a list of packages to link in.

readPackageConfigs :: DynFlags -> IO [PackageConfig] Source

getPackageConfRefs :: DynFlags -> IO [PkgConfRef] Source

resolvePackageConfig :: DynFlags -> PkgConfRef -> IO (Maybe FilePath) Source

readPackageConfig :: DynFlags -> FilePath -> IO [PackageConfig] Source

Querying the package config

lookupPackage :: DynFlags -> PackageKey -> Maybe PackageConfig Source

Find the package we know about with the given key (e.g. foo_HASH), if any

resolveInstalledPackageId :: DynFlags -> InstalledPackageId -> PackageKey Source

Looks up a PackageKey given an InstalledPackageId

searchPackageId :: DynFlags -> SourcePackageId -> [PackageConfig] Source

Search for packages with a given package ID (e.g. "foo-0.1")

getPackageDetails :: DynFlags -> PackageKey -> PackageConfig Source

Looks up the package with the given id in the package state, panicing if it is not found

listVisibleModuleNames :: DynFlags -> [ModuleName] Source

lookupModuleInAllPackages :: DynFlags -> ModuleName -> [(Module, PackageConfig)] Source

Takes a ModuleName, and if the module is in any package returns list of modules which take that name.

lookupModuleWithSuggestions :: DynFlags -> ModuleName -> Maybe FastString -> LookupResult Source

data LookupResult Source

The result of performing a lookup

Constructors

LookupFound Module PackageConfig	Found the module uniquely, nothing else to do
LookupMultiple [(Module, ModuleOrigin)]	Multiple modules with the same name in scope
LookupHidden [(Module, ModuleOrigin)] [(Module, ModuleOrigin)]	No modules found, but there were some hidden ones with an exact name match. First is due to package hidden, second is due to module being hidden
LookupNotFound [ModuleSuggestion]	Nothing found, here are some suggested different names

data ModuleSuggestion Source

Constructors

SuggestVisible ModuleName Module ModuleOrigin
SuggestHidden ModuleName Module ModuleOrigin

data ModuleOrigin Source

Package state is all stored in DynFlags, including the details of all packages, which packages are exposed, and which modules they provide.

The package state is computed by initPackages, and kept in DynFlags. It is influenced by various package flags:

-package pkg and -package-id pkg cause pkg to become exposed. If -hide-all-packages was not specified, these commands also cause all other packages with the same name to become hidden.
-hide-package pkg causes pkg to become hidden.
(there are a few more flags, check below for their semantics)

The package state has the following properties.

Let exposedPackages be the set of packages thus exposed. Let depExposedPackages be the transitive closure from exposedPackages of their dependencies.
When searching for a module from an preload import declaration, only the exposed modules in exposedPackages are valid.
When searching for a module from an implicit import, all modules from depExposedPackages are valid.
When linking in a compilation manager mode, we link in packages the program depends on (the compiler knows this list by the time it gets to the link step). Also, we link in all packages which were mentioned with preload -package flags on the command-line, or are a transitive dependency of same, or are "base"/"rts". The reason for this is that we might need packages which don't contain any Haskell modules, and therefore won't be discovered by the normal mechanism of dependency tracking.

Given a module name, there may be multiple ways it came into scope, possibly simultaneously. This data type tracks all the possible ways it could have come into scope. Warning: don't use the record functions, they're partial!

Constructors

ModHidden	Module is hidden, and thus never will be available for import. (But maybe the user didn't realize), so we'll still keep track of these modules.)
ModOrigin	Module is public, and could have come from some places.
Fields fromOrigPackage :: Maybe Bool `Just False` means that this module is in someone's `exported-modules` list, but that package is hidden; `Just True` means that it is available; `Nothing` means neither applies. fromExposedReexport :: [PackageConfig] Is the module available from a reexport of an exposed package? There could be multiple. fromHiddenReexport :: [PackageConfig] Is the module available from a reexport of a hidden package? fromPackageFlag :: Bool Did the module export come from a package flag? (ToDo: track more information.