Cabal-1.8.0.4: A framework for packaging Haskell softwareContentsIndex
Distribution.Simple.Program.Db
Portabilityportable
Maintainercabal-devel@haskell.org
Contents
The collection of configured programs we can run
Query and manipulate the program db
Query and manipulate the program db
Description

This provides a ProgramDb type which holds configured and not-yet configured programs. It is the parameter to lots of actions elsewhere in Cabal that need to look up and run programs. If we had a Cabal monad, the ProgramDb would probably be a reader or state component of it.

One nice thing about using it is that any program that is registered with Cabal will get some "configure" and ".cabal" helpers like --with-foo-args --foo-path= and extra-foo-args.

There's also a hook for adding programs in a Setup.lhs script. See hookedPrograms in Distribution.Simple.UserHooks. This gives a hook user the ability to get the above flags and such so that they don't have to write all the PATH logic inside Setup.lhs.

Synopsis
data ProgramDb
emptyProgramDb :: ProgramDb
defaultProgramDb :: ProgramDb
restoreProgramDb :: [Program] -> ProgramDb -> ProgramDb
addKnownProgram :: Program -> ProgramDb -> ProgramDb
addKnownPrograms :: [Program] -> ProgramDb -> ProgramDb
lookupKnownProgram :: String -> ProgramDb -> Maybe Program
knownPrograms :: ProgramDb -> [(Program, Maybe ConfiguredProgram)]
userSpecifyPath :: String -> FilePath -> ProgramDb -> ProgramDb
userSpecifyPaths :: [(String, FilePath)] -> ProgramDb -> ProgramDb
userMaybeSpecifyPath :: String -> Maybe FilePath -> ProgramDb -> ProgramDb
userSpecifyArgs :: String -> [ProgArg] -> ProgramDb -> ProgramDb
userSpecifyArgss :: [(String, [ProgArg])] -> ProgramDb -> ProgramDb
userSpecifiedArgs :: Program -> ProgramDb -> [ProgArg]
lookupProgram :: Program -> ProgramDb -> Maybe ConfiguredProgram
updateProgram :: ConfiguredProgram -> ProgramDb -> ProgramDb
configureProgram :: Verbosity -> Program -> ProgramDb -> IO ProgramDb
configureAllKnownPrograms :: Verbosity -> ProgramDb -> IO ProgramDb
reconfigurePrograms :: Verbosity -> [(String, FilePath)] -> [(String, [ProgArg])] -> ProgramDb -> IO ProgramDb
requireProgram :: Verbosity -> Program -> ProgramDb -> IO (ConfiguredProgram, ProgramDb)
requireProgramVersion :: Verbosity -> Program -> VersionRange -> ProgramDb -> IO (ConfiguredProgram, Version, ProgramDb)
The collection of configured programs we can run
data ProgramDb

The configuration is a collection of information about programs. It contains information both about configured programs and also about programs that we are yet to configure.

The idea is that we start from a collection of unconfigured programs and one by one we try to configure them at which point we move them into the configured collection. For unconfigured programs we record not just the Program but also any user-provided arguments and location for the program.

show/hide Instances
emptyProgramDb :: ProgramDb
defaultProgramDb :: ProgramDb
restoreProgramDb :: [Program] -> ProgramDb -> ProgramDb

The Read/Show instance does not preserve all the unconfigured Programs because Program is not in Read/Show because it contains functions. So to fully restore a deserialised ProgramDb use this function to add back all the known Programs.

  • It does not add the default programs, but you probably want them, use builtinPrograms in addition to any extra you might need.
Query and manipulate the program db
addKnownProgram :: Program -> ProgramDb -> ProgramDb
Add a known program that we may configure later
addKnownPrograms :: [Program] -> ProgramDb -> ProgramDb
lookupKnownProgram :: String -> ProgramDb -> Maybe Program
knownPrograms :: ProgramDb -> [(Program, Maybe ConfiguredProgram)]
userSpecifyPath
:: StringProgram name
-> FilePathuser-specified path to the program
-> ProgramDb
-> ProgramDb
User-specify this path. Basically override any path information for this program in the configuration. If it's not a known program ignore it.
userSpecifyPaths :: [(String, FilePath)] -> ProgramDb -> ProgramDb
Like userSpecifyPath but for a list of progs and their paths.
userMaybeSpecifyPath :: String -> Maybe FilePath -> ProgramDb -> ProgramDb
userSpecifyArgs
:: StringProgram name
-> [ProgArg]user-specified args
-> ProgramDb
-> ProgramDb
User-specify the arguments for this program. Basically override any args information for this program in the configuration. If it's not a known program, ignore it..
userSpecifyArgss :: [(String, [ProgArg])] -> ProgramDb -> ProgramDb
Like userSpecifyPath but for a list of progs and their args.
userSpecifiedArgs :: Program -> ProgramDb -> [ProgArg]
Get any extra args that have been previously specified for a program.
lookupProgram :: Program -> ProgramDb -> Maybe ConfiguredProgram
Try to find a configured program
updateProgram :: ConfiguredProgram -> ProgramDb -> ProgramDb
Update a configured program in the database.
Query and manipulate the program db
configureProgram :: Verbosity -> Program -> ProgramDb -> IO ProgramDb

Try to configure a specific program. If the program is already included in the colleciton of unconfigured programs then we use any user-supplied location and arguments. If the program gets configured sucessfully it gets added to the configured collection.

Note that it is not a failure if the program cannot be configured. It's only a failure if the user supplied a location and the program could not be found at that location.

The reason for it not being a failure at this stage is that we don't know up front all the programs we will need, so we try to configure them all. To verify that a program was actually sucessfully configured use requireProgram.

configureAllKnownPrograms :: Verbosity -> ProgramDb -> IO ProgramDb
Try to configure all the known programs that have not yet been configured.
reconfigurePrograms :: Verbosity -> [(String, FilePath)] -> [(String, [ProgArg])] -> ProgramDb -> IO ProgramDb
reconfigure a bunch of programs given new user-specified args. It takes the same inputs as userSpecifyPath and userSpecifyArgs and for all progs with a new path it calls configureProgram.
requireProgram :: Verbosity -> Program -> ProgramDb -> IO (ConfiguredProgram, ProgramDb)

Check that a program is configured and available to be run.

It raises an exception if the program could not be configured, otherwise it returns the configured program.

requireProgramVersion :: Verbosity -> Program -> VersionRange -> ProgramDb -> IO (ConfiguredProgram, Version, ProgramDb)

Check that a program is configured and available to be run.

Additionally check that the version of the program number is suitable and return it. For example you could require AnyVersion or orLaterVersion (Version [1,0] [])

It raises an exception if the program could not be configured or the version is unsuitable, otherwise it returns the configured program and its version number.

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