-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/
-- | Print currently playing MPD's song metadata and status as JSON
@package mpd-current-json
@version 1.1.0.2
module Paths_mpd_current_json
version :: Version
getBinDir :: IO FilePath
getLibDir :: IO FilePath
getDynLibDir :: IO FilePath
getDataDir :: IO FilePath
getLibexecDir :: IO FilePath
getDataFileName :: FilePath -> IO FilePath
getSysconfDir :: IO FilePath
module Version
versionStr :: [Char]
progName :: [Char]
module Options
data Opts
-- | Custom data record for storing Parser values
Opts :: Integer -> String -> String -> (Type -> Type) -> Opts
-- | MPD port to connect.
[optPort] :: Opts -> Integer
-- | MPD host address to connect.
[optHost] :: Opts -> String
-- | Plain text password to connect to MPD.
[optPass] :: Opts -> String
-- | Print program version.
[optVersion] :: Opts -> Type -> Type
-- | Run a program description.
--
-- Parse command line arguments. Display help text and exit if any parse
-- error occurs.
execParser :: ParserInfo a -> IO a
-- | Create a ParserPrefs given a modifier
prefs :: PrefsMod -> ParserPrefs
-- | Show the help text if the user enters only the program name or
-- subcommand.
--
-- This will suppress a "Missing:" error and show the full usage instead
-- if a user just types the name of the program.
showHelpOnEmpty :: PrefsMod
optsParser :: Parser Opts
optsParserInfo :: ParserInfo Opts
module Main
-- | Where the program connects to MPD and uses the helper functions to
-- extract values, organize them into a list of key/value pairs, make
-- them a Value using object, then encode it to a
-- conventional JSON ByteString with encodePretty for the
-- pretty-print version.
main :: IO ()
-- | Extract a field from the returned MPD.Status data record.
--
-- This takes an Either MPDError Status value and
-- a field label function f as arguments. It returns Just (f
-- st) if the input status is Right st, where st
-- is the Status value. This function helps to extract a specific
-- field from the MPD.Status data record by providing the
-- corresponding field label function. If the input status "st"
-- is not Right st, indicating an error, or the field label
-- function is not applicable, it returns Nothing.
getStatusItem :: Either MPDError Status -> (Status -> a) -> Maybe a
-- | Either check for the returned value of currentSong,
-- then call processSong or return Nothing.
getTag :: Metadata -> Either a (Maybe Song) -> Maybe String
-- | Use sgGetTag to extract a tag from a song,
-- safely get only the head item of the returned Maybe list,
-- then safely convert it to a string.
processSong :: Metadata -> Maybe Song -> Maybe String
-- | Safely get the head of a list. Same as headMay.
headMay :: [a] -> Maybe a
-- | Convert Value to String within a Maybe
-- context.
--
-- This Value is from MPD and is basically the same as a
-- String but used internally to store metadata values.
--
-- Example:
--
--
-- processSong :: Metadata -> Maybe Song -> Maybe String
-- processSong _ Nothing = Nothing
-- processSong tag (Just song) = do
-- let tagVal = MPD.sgGetTag tag song
-- valueToStringMay =<< (headMay =<< tagVal)
--
--
-- sgGetTag returns a Maybe [Value]. MPD also
-- provides toString that can convert, along other types, a
-- Value to a String.
valueToStringMay :: Value -> Maybe String
-- | Check if Maybe v exists and is of type expected by
-- object as defined in Value, if it is return both the
-- key and value within the Maybe context tied
-- with .=. This gives support to 'optional' fields using
-- catMaybes that discard Nothing values and is meant to
-- prevent creating JSON key/value pairs with null values, e.g.:
--
--
-- jsonTags = object . catMaybes $
-- [ "artist" .=? artist
-- , "album" .=? album
-- , "title" .=? title
-- ]
--
--
-- Where if a value on the right is Nothing that key/value pair
-- will not be included in object because of catMaybes.
(.=?) :: (KeyValue a, ToJSON v) => Key -> Maybe v -> Maybe a