Generate XMonad workspace names from a range of numbers with optional descriptive suffixes.

workspacenames.hs

-----------------------------------------
-- | Generate workspace names for XMonad.
-----------------------------------------


import qualified Data.List as List
import qualified Data.Map as Map


-- | A workspace's number.
--
-- If a workspace's name starts with a number, one can switch to that
-- workspace using the configured modifier key with that number.
newtype WorkspaceNumber = WNumber Integer deriving (Eq, Ord)


-- | A workspace suffix.
--
-- It will be appended to the workspace's number.
newtype WorkspaceSuffix = WSuffix String deriving (Eq, Ord)


-- | A mapping from workspace suffixes to workspace numbers.
type SuffixesByNumber = Map.Map WorkspaceNumber WorkspaceSuffix


-- | Map workspace numbers to suffixes.
mapNumbersToSuffixes :: [(Integer, String)] -> SuffixesByNumber
mapNumbersToSuffixes numberAndSuffixPairs = Map.fromList (map parse numberAndSuffixPairs)
    where
        parse (numberRaw, suffixRaw) = (WNumber numberRaw, WSuffix suffixRaw)


-- | Generate a workspace's name from its number and, if available, a suffix.
determineName :: SuffixesByNumber -> WorkspaceNumber -> String
determineName suffixesByNumber k = case Map.lookup k suffixesByNumber of
    Nothing -> extractNumberValue k
    Just v -> (extractNumberValue k) ++ ":" ++ (extractSuffixValue v)
    where
        extractNumberValue (WNumber x) = show x
        extractSuffixValue (WSuffix x) = x


-- expected result:
--   ["1:web", "2", "3", "4", "5:mail", "6", "7", "8", "9"]

numbers = map WNumber [1..9]
suffixesByNumber = mapNumbersToSuffixes [
    (1, "web"),
    (5, "mail")
    ]
names = map (determineName suffixesByNumber) numbers


join :: [String] -> String
join xs = List.intercalate ", " xs


main = do
    putStrLn ("workspace names: " ++ join names)