Darcs.Utils

Various utility functions that do not belong anywhere else.

Documentation

ortryrunning :: IO ExitCode -> IO ExitCode -> IO ExitCode

Given two shell commands as arguments, execute the former. The latter is then executed if the former failed because the executable wasn't found (code 127), wasn't executable (code 126) or some other exception occurred. Other failures (such as the user holding ^C) do not cause the second command to be tried.

nubsort :: Ord a => [a] -> [a]

breakCommand :: String -> (String, [String])

showHexLen :: (Integral a, Show a) => Int -> a -> String

maybeGetEnv :: String -> IO (Maybe String)

formatPath :: String -> String

Format a path for screen output, so that the user sees where the path begins and ends. Could (should?) also warn about unprintable characters here.

Monads

firstJustIO :: [IO (Maybe a)] -> IO (Maybe a)

The firstJustIO is a slight modification to firstJustM: the entries in the list must be IO monad operations and the firstJustIO will silently turn any monad call that throws an exception into Nothing, basically causing it to be ignored.

User prompts

askEnter

Arguments

:: String

The prompt to display

-> IO ()

Ask the user to press Enter

askUser

Arguments

:: String

The prompt to display

-> IO String

The string the user entered.

Ask the user for a line of input.

askUserListItem :: String -> [String] -> IO String

askUserListItem prompt xs enumerates xs on the screen, allowing the user to choose one of the items

data PromptConfig

Constructors

PromptConfig

Fields

pPrompt :: String

pBasicCharacters :: [Char]

pAdvancedCharacters :: [Char]

only shown on help

pDefault :: Maybe Char

pHelp :: [Char]

promptYorn :: [Char] -> IO Bool

Prompt the user for a yes or no

promptChar :: PromptConfig -> IO Char

Text

getViewer :: IO String

editFile :: FilePathLike p => p -> IO (ExitCode, Bool)

editFile f lets the user edit a file which could but does not need to already exist. This function returns the exit code from the text editor and a flag indicating if the user made any changes.

runEditor :: FilePath -> IO ExitCode

stripCr :: String -> String

Help

environmentHelpEditor :: ([String], [String])

environmentHelpPager :: ([String], [String])

Errors and exceptions

catchall :: IO a -> IO a -> IO a

clarifyErrors :: IO a -> String -> IO a

prettyException :: SomeException -> String

prettyError :: IOError -> String

addToErrorLoc :: IOException -> String -> IOException

Files and directories

getFileStatus :: FilePath -> IO (Maybe FileStatus)

withCurrentDirectory :: FilePathLike p => p -> IO a -> IO a

withUMask :: String -> IO a -> IO a

setDarcsEncodings :: IO ()

In some environments, darcs requires that certain global GHC library variables that control the encoding used in internal translations are set to specific values.

setDarcsEncoding enforces those settings, and should be called before the first time any darcs operation is run, and again if anything else might have set those encodings to different values.

Note that it isn't thread-safe and has a global effect on your program.

The current behaviour of this function is as follows, though this may change in future:

Encodings are only set on GHC 7.4 and up, on any non-Windows platform.

Two encodings are set, both to GHC.IO.Encoding.char8: GHC.IO.Encoding.setFileSystemEncoding and GHC.IO.Encoding.setForeignEncoding.

getSystemEncoding :: IO String

isUTF8Locale :: String -> Bool

isUTF8 checks if an encoding is UTF-8 (or ascii, since it is a subset of UTF-8).

Tree filtering.

filterFilePaths :: [FilePath] -> AnchoredPath -> t -> Bool

Same as filterPath, but for ordinary FilePaths (as opposed to AnchoredPath).

filterPaths :: [AnchoredPath] -> AnchoredPath -> t -> Bool

Construct a filter from a list of AnchoredPaths, that will accept any path that is either a parent or a child of any of the listed paths, and discard everything else.

Tree lookup.

treeHas :: (MonadError e m, Functor m, Monad m) => Tree m -> FilePath -> m Bool

treeHasDir :: (MonadError e m, Functor m, Monad m) => Tree m -> FilePath -> m Bool

treeHasFile :: (MonadError e m, Functor m, Monad m) => Tree m -> FilePath -> m Bool

treeHasAnycase :: (MonadError e m, Functor m, Monad m) => Tree m -> FilePath -> m Bool