Cabal-1.6.0.2: A framework for packaging Haskell softwareContentsIndex
Distribution.Simple.Program
Portabilityportable
Maintainercabal-devel@haskell.org
Contents
Program and functions for constructing them
Configured program and related functions
The collection of unconfigured and configured progams
The collection of configured programs we can run
Programs that Cabal knows about
Description

This provides an abstraction which deals with configuring and running programs. A Program is a static notion of a known program. A ConfiguredProgram is a Program that has been found on the current machine and is ready to be run (possibly with some user-supplied default args). Configuring a program involves finding its location and if necessary finding its version. There is also a ProgramConfiguration 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 ProgramConfiguration would probably be a reader or state component of it.

The module also defines all the known built-in Programs and the defaultProgramConfiguration which contains them all.

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 good default behavior for trying to find "foo" in PATH, being able to override its location, etc.

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 Program = Program {
programName :: String
programFindLocation :: Verbosity -> IO (Maybe FilePath)
programFindVersion :: Verbosity -> FilePath -> IO (Maybe Version)
programPostConf :: Verbosity -> ConfiguredProgram -> IO [ProgArg]
}
simpleProgram :: String -> Program
findProgramOnPath :: FilePath -> Verbosity -> IO (Maybe FilePath)
findProgramVersion :: ProgArg -> (String -> String) -> Verbosity -> FilePath -> IO (Maybe Version)
data ConfiguredProgram = ConfiguredProgram {
programId :: String
programVersion :: Maybe Version
programArgs :: [ProgArg]
programLocation :: ProgramLocation
}
programPath :: ConfiguredProgram -> FilePath
type ProgArg = String
data ProgramLocation
= UserSpecified {
locationPath :: FilePath
}
| FoundOnSystem {
locationPath :: FilePath
}
rawSystemProgram :: Verbosity -> ConfiguredProgram -> [ProgArg] -> IO ()
rawSystemProgramStdout :: Verbosity -> ConfiguredProgram -> [ProgArg] -> IO String
builtinPrograms :: [Program]
data ProgramConfiguration
emptyProgramConfiguration :: ProgramConfiguration
defaultProgramConfiguration :: ProgramConfiguration
restoreProgramConfiguration :: [Program] -> ProgramConfiguration -> ProgramConfiguration
addKnownProgram :: Program -> ProgramConfiguration -> ProgramConfiguration
addKnownPrograms :: [Program] -> ProgramConfiguration -> ProgramConfiguration
lookupKnownProgram :: String -> ProgramConfiguration -> Maybe Program
knownPrograms :: ProgramConfiguration -> [(Program, Maybe ConfiguredProgram)]
userSpecifyPath :: String -> FilePath -> ProgramConfiguration -> ProgramConfiguration
userSpecifyPaths :: [(String, FilePath)] -> ProgramConfiguration -> ProgramConfiguration
userMaybeSpecifyPath :: String -> Maybe FilePath -> ProgramConfiguration -> ProgramConfiguration
userSpecifyArgs :: String -> [ProgArg] -> ProgramConfiguration -> ProgramConfiguration
userSpecifyArgss :: [(String, [ProgArg])] -> ProgramConfiguration -> ProgramConfiguration
userSpecifiedArgs :: Program -> ProgramConfiguration -> [ProgArg]
lookupProgram :: Program -> ProgramConfiguration -> Maybe ConfiguredProgram
updateProgram :: ConfiguredProgram -> ProgramConfiguration -> ProgramConfiguration
configureProgram :: Verbosity -> Program -> ProgramConfiguration -> IO ProgramConfiguration
configureAllKnownPrograms :: Verbosity -> ProgramConfiguration -> IO ProgramConfiguration
reconfigurePrograms :: Verbosity -> [(String, FilePath)] -> [(String, [ProgArg])] -> ProgramConfiguration -> IO ProgramConfiguration
requireProgram :: Verbosity -> Program -> VersionRange -> ProgramConfiguration -> IO (ConfiguredProgram, ProgramConfiguration)
rawSystemProgramConf :: Verbosity -> Program -> ProgramConfiguration -> [ProgArg] -> IO ()
rawSystemProgramStdoutConf :: Verbosity -> Program -> ProgramConfiguration -> [ProgArg] -> IO String
ghcProgram :: Program
ghcPkgProgram :: Program
nhcProgram :: Program
hmakeProgram :: Program
jhcProgram :: Program
hugsProgram :: Program
ffihugsProgram :: Program
gccProgram :: Program
ranlibProgram :: Program
arProgram :: Program
stripProgram :: Program
happyProgram :: Program
alexProgram :: Program
hsc2hsProgram :: Program
c2hsProgram :: Program
cpphsProgram :: Program
hscolourProgram :: Program
haddockProgram :: Program
greencardProgram :: Program
ldProgram :: Program
tarProgram :: Program
cppProgram :: Program
pkgConfigProgram :: Program
Program and functions for constructing them
data Program
Represents a program which can be configured.
Constructors
Program
programName :: StringThe simple name of the program, eg. ghc
programFindLocation :: Verbosity -> IO (Maybe FilePath)A function to search for the program if it's location was not specified by the user. Usually this will just be a
programFindVersion :: Verbosity -> FilePath -> IO (Maybe Version)Try to find the version of the program. For many programs this is not possible or is not necessary so it's ok to return Nothing.
programPostConf :: Verbosity -> ConfiguredProgram -> IO [ProgArg]A function to do any additional configuration after we have located the program (and perhaps identified its version). It is allowed to return additional flags that will be passed to the program on every invocation.
simpleProgram :: String -> Program

Make a simple named program.

By default we'll just search for it in the path and not try to find the version name. You can override these behaviours if necessary, eg:

 simpleProgram "foo" { programFindLocation = ... , programFindVersion ... }
findProgramOnPath :: FilePath -> Verbosity -> IO (Maybe FilePath)
Look for a program on the path.
findProgramVersion
:: ProgArgversion args
-> String -> Stringfunction to select version number from program output
-> Verbosity
-> FilePathlocation
-> IO (Maybe Version)
Look for a program and try to find it's version number. It can accept either an absolute path or the name of a program binary, in which case we will look for the program on the path.
Configured program and related functions
data ConfiguredProgram
Constructors
ConfiguredProgram
programId :: StringJust the name again
programVersion :: Maybe VersionThe version of this program, if it is known.
programArgs :: [ProgArg]Default command-line args for this program. These flags will appear first on the command line, so they can be overridden by subsequent flags.
programLocation :: ProgramLocationLocation of the program. eg. /usr/bin/ghc-6.4
show/hide Instances
programPath :: ConfiguredProgram -> FilePath
The full path of a configured program.
type ProgArg = String
data ProgramLocation
Where a program was found. Also tells us whether it's specifed by user or not. This includes not just the path, but the program as well.
Constructors
UserSpecifiedThe user gave the path to this program, eg. --ghc-path=/usr/bin/ghc-6.6
locationPath :: FilePath
FoundOnSystemThe location of the program, as located by searching PATH.
locationPath :: FilePath
show/hide Instances
rawSystemProgram
:: VerbosityVerbosity
-> ConfiguredProgramThe program to run
-> [ProgArg]Any extra arguments to add
-> IO ()
Runs the given configured program.
rawSystemProgramStdout
:: VerbosityVerbosity
-> ConfiguredProgramThe program to run
-> [ProgArg]Any extra arguments to add
-> IO String
Runs the given configured program and gets the output.
The collection of unconfigured and configured progams
builtinPrograms :: [Program]
The default list of programs. These programs are typically used internally to Cabal.
The collection of configured programs we can run
data ProgramConfiguration

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
emptyProgramConfiguration :: ProgramConfiguration
defaultProgramConfiguration :: ProgramConfiguration
restoreProgramConfiguration :: [Program] -> ProgramConfiguration -> ProgramConfiguration

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 ProgramConfiguration 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.
addKnownProgram :: Program -> ProgramConfiguration -> ProgramConfiguration
Add a known program that we may configure later
addKnownPrograms :: [Program] -> ProgramConfiguration -> ProgramConfiguration
lookupKnownProgram :: String -> ProgramConfiguration -> Maybe Program
knownPrograms :: ProgramConfiguration -> [(Program, Maybe ConfiguredProgram)]
userSpecifyPath
:: StringProgram name
-> FilePathuser-specified path to the program
-> ProgramConfiguration
-> ProgramConfiguration
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)] -> ProgramConfiguration -> ProgramConfiguration
Like userSpecifyPath but for a list of progs and their paths.
userMaybeSpecifyPath :: String -> Maybe FilePath -> ProgramConfiguration -> ProgramConfiguration
userSpecifyArgs
:: StringProgram name
-> [ProgArg]user-specified args
-> ProgramConfiguration
-> ProgramConfiguration
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])] -> ProgramConfiguration -> ProgramConfiguration
Like userSpecifyPath but for a list of progs and their args.
userSpecifiedArgs :: Program -> ProgramConfiguration -> [ProgArg]
Get any extra args that have been previously specified for a program.
lookupProgram :: Program -> ProgramConfiguration -> Maybe ConfiguredProgram
Try to find a configured program
updateProgram :: ConfiguredProgram -> ProgramConfiguration -> ProgramConfiguration
Update a configured program in the database.
configureProgram :: Verbosity -> Program -> ProgramConfiguration -> IO ProgramConfiguration

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 -> ProgramConfiguration -> IO ProgramConfiguration
Try to configure all the known programs that have not yet been configured.
reconfigurePrograms :: Verbosity -> [(String, FilePath)] -> [(String, [ProgArg])] -> ProgramConfiguration -> IO ProgramConfiguration
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 -> VersionRange -> ProgramConfiguration -> IO (ConfiguredProgram, ProgramConfiguration)

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

Additionally check that the version of the program number is suitable. For example 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.

rawSystemProgramConf
:: Verbosityverbosity
-> ProgramThe program to run
-> ProgramConfigurationlook up the program here
-> [ProgArg]Any extra arguments to add
-> IO ()
Looks up the given program in the program configuration and runs it.
rawSystemProgramStdoutConf
:: Verbosityverbosity
-> ProgramThe program to run
-> ProgramConfigurationlook up the program here
-> [ProgArg]Any extra arguments to add
-> IO String
Looks up the given program in the program configuration and runs it.
Programs that Cabal knows about
ghcProgram :: Program
ghcPkgProgram :: Program
nhcProgram :: Program
hmakeProgram :: Program
jhcProgram :: Program
hugsProgram :: Program
ffihugsProgram :: Program
gccProgram :: Program
ranlibProgram :: Program
arProgram :: Program
stripProgram :: Program
happyProgram :: Program
alexProgram :: Program
hsc2hsProgram :: Program
c2hsProgram :: Program
cpphsProgram :: Program
hscolourProgram :: Program
haddockProgram :: Program
greencardProgram :: Program
ldProgram :: Program
tarProgram :: Program
cppProgram :: Program
pkgConfigProgram :: Program
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