Cabal-1.8.0.2: A framework for packaging Haskell softwareContentsIndex
Distribution.Simple.Program.Types
Portabilityportable
Maintainercabal-devel@haskell.org
Contents
Program and functions for constructing them
Configured program and related functions
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's reasonable default behavior for trying to find "foo" in PATH, being able to override its location, etc.
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
data ConfiguredProgram = ConfiguredProgram {
programId :: String
programVersion :: Maybe Version
programArgs :: [String]
programLocation :: ProgramLocation
}
programPath :: ConfiguredProgram -> FilePath
type ProgArg = String
data ProgramLocation
= UserSpecified {
locationPath :: FilePath
}
| FoundOnSystem {
locationPath :: FilePath
}
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 ... }
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 :: [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.
programLocation :: ProgramLocationLocation of the program. eg. /usr/bin/ghc-6.4
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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
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