| Copyright | Duncan Coutts 2013 |
|---|---|
| Maintainer | cabal-devel@haskell.org |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Distribution.Simple.Program.Find
Contents
Description
A somewhat extended notion of the normal program search path concept.
Usually when finding executables we just want to look in the usual places
using the OS's usual method for doing so. In Haskell the normal OS-specific
method is captured by findExecutable. On all common OSs that makes use of
a PATH environment variable, (though on Windows it is not just the PATH).
However it is sometimes useful to be able to look in additional locations
without having to change the process-global PATH environment variable.
So we need an extension of the usual findExecutable that can look in
additional locations, either before, after or instead of the normal OS
locations.
Synopsis
- type ProgramSearchPath = [ProgramSearchPathEntry]
- data ProgramSearchPathEntry
- defaultProgramSearchPath :: ProgramSearchPath
- findProgramOnSearchPath :: Verbosity -> ProgramSearchPath -> FilePath -> IO (Maybe (FilePath, [FilePath]))
- programSearchPathAsPATHVar :: ProgramSearchPath -> IO String
- logExtraProgramSearchPath :: Verbosity -> [FilePath] -> IO ()
- getSystemSearchPath :: IO [FilePath]
- getExtraPathEnv :: Verbosity -> [(String, Maybe String)] -> [FilePath] -> IO [(String, Maybe String)]
- simpleProgram :: String -> Program
Program search path
type ProgramSearchPath = [ProgramSearchPathEntry] Source #
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]
We also use this path to set the environment when running child processes.
The ProgramDb is created with a ProgramSearchPath to which we
prependProgramSearchPath to add the ones that come from cli flags and from
configurations. Then each of the programs that are configured in the db
inherits the same path as part of configureProgram.
data ProgramSearchPathEntry Source #
Constructors
| ProgramSearchPathDir FilePath | A specific dir |
| ProgramSearchPathDefault | The system default |
Instances
findProgramOnSearchPath :: Verbosity -> ProgramSearchPath -> FilePath -> IO (Maybe (FilePath, [FilePath])) Source #
programSearchPathAsPATHVar :: ProgramSearchPath -> IO String Source #
Interpret a ProgramSearchPath to construct a new $PATH env var.
Note that this is close but not perfect because on Windows the search
algorithm looks at more than just the %PATH%.
getSystemSearchPath :: IO [FilePath] Source #
Get the system search path. On Unix systems this is just the $PATH env
var, but on windows it's a bit more complicated.
getExtraPathEnv :: Verbosity -> [(String, Maybe String)] -> [FilePath] -> IO [(String, Maybe String)] Source #
Adds some paths to the PATH entry in the key-value environment provided
or if there is none, looks up $PATH in the real environment.
simpleProgram :: String -> Program Source #
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 ... }