Add.hs

   1 module Add (
   2     add,
   3     usageAdd
   4 ) where
   5
   6 import Data.List
   7 import Util
   8
   9 data Flag = Path String
  10           | Title String
  11           | Authors String
  12           | Keywords String
  13           | Journal String
  14           | Issue String
  15           | Date String
  16           | Pages String
  17           deriving (Show)
  18
  19 isFlag :: String -> Bool
  20 isFlag f = f `elem` ["-f","-p","-t","-j","-i","-d","-a","-k"]
  21
  22 add :: [String] -> IO ()
  23 add [] = error $ "add: no arguments specified ('" ++ progName ++ " add help' for help)"
  24 add argv = if isHelp $ head argv
  25     then do putStrLn usageAdd
  26     else do
  27         case parseFlags argv of
  28             Left  msg   -> error $ "add: " ++ msg
  29             Right flags -> putStr $ flagsToString flags
  30
  31 flagsToString :: [Flag] -> String
  32 flagsToString xs = foldl' step [] xs
  33     where step ys x = show x ++ "\n" ++ ys
  34
  35 parseFlags :: [String] -> Either String [Flag]
  36 parseFlags argv = parseFlags' [] argv
  37     where parseFlags' _  (x:[]) = Left "too few arguments"
  38           parseFlags' fs []     = Right fs
  39           parseFlags' fs xs     =
  40               let flag = getFlag xs
  41               in case flag of
  42                   Left  msg  -> Left msg
  43                   Right f    -> parseFlags' (f:fs) (dropWhile (not . isFlag) (tail xs))
  44
  45 getFlag :: [String] -> Either String Flag
  46 getFlag x@(x0:x1:_) =
  47     let flag = case x0 of
  48                    "-f" -> Path    x1
  49                    "-t" -> Title   x1
  50                    "-j" -> Journal x1
  51                    "-i" -> Issue   x1
  52                    "-d" -> Date    x1
  53                    "-p" -> Pages   x1
  54                    "-k" -> Keywords $ getValues $ tail  x
  55                    "-a" -> Authors  $ getValues $ tail  x
  56     in if isFlag x1
  57            then Left "too few argument"
  58            else Right flag
  59
  60 getValues :: [String] -> String
  61 getValues argv = intercalate "|" $ takeWhile (not . isFlag) argv
  62
  63 usageAdd :: String
  64 usageAdd = "usage: " ++ progName ++ " add <filters>\n\
  65             \filters:\n\
  66             \    -f <file>\n\
  67             \    -t <title>\n\
  68             \    -a <author1 [author2] ...>\n\
  69             \    -k <keyword1 [keyword2] ...>\n\
  70             \    -j <journal>\n\
  71             \    -i <issue>\n\
  72             \    -d <date>\n\
  73             \    -p <page-from>-<page-to>"