Portability	portable
Maintainer	cabal-devel@haskell.org
Safe Haskell	None

Distribution.Simple.Program

Contents

Program and functions for constructing them
Configured program and related functions
Program invocations
The collection of unconfigured and configured programs
The collection of configured programs we can run
Programs that Cabal knows about
deprecated

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 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

Program and functions for constructing them

data Program

Represents a program which can be configured.

Note: rather than constructing this directly, start with simpleProgram and override any extra fields.

Constructors

Program

Fields

programName :: String

The simple name of the program, eg. ghc

programFindLocation :: Verbosity -> ProgramSearchPath -> IO (Maybe FilePath)

A function to search for the program if its location was not specified by the user. Usually this will just be a call to findProgramOnSearchPath.

It is supplied with the prevailing search path which will typically just be used as-is, but can be extended or ignored as needed.

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 ConfiguredProgram

A function to do any additional configuration after we have located the program (and perhaps identified its version). For example it could add args, or environment vars.

type ProgramSearchPath = [ProgramSearchPathEntry]

A search path to use when locating executables. This is analogous to the unix $PATH or win32 %PATH% but with the ability to use the system default method for finding executables (findExecutable which on unix is simply looking on the $PATH but on win32 is a bit more complicated).

The default to use is [ProgSearchPathDefault] but you can add extra dirs either before, after or instead of the default, e.g. here we add an extra dir to search after the usual ones.

 ['ProgramSearchPathDefault', 'ProgramSearchPathDir' dir]

data ProgramSearchPathEntry

Constructors

ProgramSearchPathDir FilePath	A specific dir
ProgramSearchPathDefault	The system default

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 ... }

findProgramLocation :: Verbosity -> FilePath -> IO (Maybe FilePath)

Look for a program on the path.

findProgramVersion

Arguments

:: String	version args
-> (String -> String)	function to select version number from program output
-> Verbosity
-> FilePath	location
-> 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

Represents a program which has been configured and is thus ready to be run.

These are usually made by configuring a Program, but if you have to construct one directly then start with simpleConfiguredProgram and override any extra fields.

Constructors

ConfiguredProgram

Fields

programId :: String: Just the name again
programVersion :: Maybe Version: The version of this program, if it is known.
programDefaultArgs :: [String]: Default command-line args for this program. These flags will appear first on the command line, so they can be overridden by subsequent flags.
programOverrideArgs :: [String]: Override command-line args for this program. These flags will appear last on the command line, so they override all earlier flags.
programOverrideEnv :: [(String, Maybe String)]: Override environment variables for this program. These env vars will extend/override the prevailing environment of the current to form the environment for the new process.
programLocation :: ProgramLocation: Location of the program. eg. /usr/bin/ghc-6.4

Instances

Eq ConfiguredProgram
Read ConfiguredProgram
Show ConfiguredProgram

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 specified by user or not. This includes not just the path, but the program as well.

Constructors

UserSpecified	The user gave the path to this program, eg. --ghc-path=/usr/bin/ghc-6.6
Fields locationPath :: FilePath
FoundOnSystem	The program was found automatically.
Fields locationPath :: FilePath

Instances

Eq ProgramLocation
Read ProgramLocation
Show ProgramLocation

runProgram

Arguments

:: Verbosity	Verbosity
-> ConfiguredProgram	The program to run
-> [ProgArg]	Any extra arguments to add
-> IO ()

Runs the given configured program.

getProgramOutput

Arguments

:: Verbosity	Verbosity
-> ConfiguredProgram	The program to run
-> [ProgArg]	Any extra arguments to add
-> IO String

Runs the given configured program and gets the output.

suppressOverrideArgs :: ConfiguredProgram -> ConfiguredProgram

Suppress any extra arguments added by the user.

Program invocations

data ProgramInvocation

Represents a specific invocation of a specific program.

This is used as an intermediate type between deciding how to call a program and actually doing it. This provides the opportunity to the caller to adjust how the program will be called. These invocations can either be run directly or turned into shell or batch scripts.

Constructors

ProgramInvocation
Fields progInvokePath :: FilePath progInvokeArgs :: [String] progInvokeEnv :: [(String, Maybe String)] progInvokeCwd :: Maybe FilePath progInvokeInput :: Maybe String progInvokeInputEncoding :: IOEncoding progInvokeOutputEncoding :: IOEncoding

emptyProgramInvocation :: ProgramInvocation

simpleProgramInvocation :: FilePath -> [String] -> ProgramInvocation

programInvocation :: ConfiguredProgram -> [String] -> ProgramInvocation

runProgramInvocation :: Verbosity -> ProgramInvocation -> IO ()

getProgramInvocationOutput :: Verbosity -> ProgramInvocation -> IO String

The collection of unconfigured and configured programs

builtinPrograms :: [Program]

The default list of programs. These programs are typically used internally to Cabal.

The collection of configured programs we can run

type ProgramConfiguration = ProgramDb

emptyProgramConfiguration :: ProgramConfiguration

defaultProgramConfiguration :: ProgramConfiguration

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

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)]

getProgramSearchPath :: ProgramDb -> ProgramSearchPath

Get the current ProgramSearchPath used by the ProgramDb. This is the default list of locations where programs are looked for when configuring them. This can be overridden for specific programs (with userSpecifyPath), and specific known programs can modify or ignore this search path in their own configuration code.

setProgramSearchPath :: ProgramSearchPath -> ProgramDb -> ProgramDb

Change the current ProgramSearchPath used by the ProgramDb. This will affect programs that are configured from here on, so you should usually set it before configuring any programs.

userSpecifyPath

Arguments

:: String	Program name
-> FilePath	user-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

Arguments

:: String	Program 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.

configureProgram :: Verbosity -> Program -> ProgramDb -> IO ProgramDb

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

runDbProgram

Arguments