add schedule command

Mostly because it gives me an excuse and a hook to document the schedule
expression format.

Command/Schedule.hs

@@ -0,0 +1,50 @@
+{- git-annex command
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.Schedule where
+
+import Common.Annex
+import Command
+import qualified Remote
+import Logs.Schedule
+import Types.ScheduledActivity
+
+import qualified Data.Set as S
+
+def :: [Command]
+def = [command "schedule" (paramPair paramRemote (paramOptional paramExpression)) seek
+	SectionSetup "get or set scheduled jobs"]
+
+seek :: [CommandSeek]
+seek = [withWords start]
+
+start :: [String] -> CommandStart
+start = parse
+  where
+  	parse (name:[]) = go name performGet
+	parse (name:expr:[]) = go name $ \uuid -> do
+		showStart "schedile" name
+		performSet expr uuid
+	parse _ = error "Specify a repository."
+
+	go name a = do
+		u <- Remote.nameToUUID name
+		next $ a u
+
+performGet :: UUID -> CommandPerform
+performGet uuid = do
+	s <- scheduleGet uuid
+	liftIO $ putStrLn $ intercalate "; " $ 
+		map fromScheduledActivity $ S.toList s
+	next $ return True
+
+performSet :: String -> UUID -> CommandPerform
+performSet expr uuid = case parseScheduledActivities expr of
+	Left e -> error $ "Parse error: " ++ e
+	Right l -> do
+		scheduleSet uuid l
+		next $ return True