src/Modify.hs

   1 {-
   2     Modify.hs
   3
   4     Copyright 2013 Louis-Guillaume Gagnon <louis.guillaume.gagnon@gmail.com>
   5
   6     This program is free software: you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation, either version 3 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 -}
  19
  20 module Modify (
  21     modify,
  22     usageModify
  23 ) where
  24
  25 import Data.Char (isDigit)
  26
  27 import Tools.Constants
  28 import Tools.Filter (tryGetFilters,updatePairs)
  29 import Tools.Operation (isHelp)
  30 import Tools.SQL (getEntry,modifyEntry)
  31
  32 modify :: [String] -> IO ()
  33 modify []      = error errTooFew
  34 modify (f:[])  = if isHelp f then putStrLn usageModify else error errTooFew
  35 modify (id:fs) = if or (map (not . isDigit) id)
  36                      then error $ "modify: invalid id: " ++ id
  37                      else do entry <- getEntry $ read id
  38                              case entry of
  39                                  Left msg -> error $ "modify: " ++ msg
  40                                  Right row -> do filters <- tryGetFilters fs
  41                                                  case filters of
  42                                                     Left msg -> error $ "modify: " ++ msg
  43                                                     Right fs' -> doModify row fs'
  44
  45 doModify :: [String] -> ([String],[String]) -> IO ()
  46 doModify row new = return (updatePairs row new) >>= modifyEntry (read (row!!0))
  47
  48 errTooFew :: String
  49 errTooFew = "modify: too few arguments ('" ++ progName ++ " modify help' for help)"
  50
  51 usageModify :: String
  52 usageModify = "usage: " ++ progName ++ " modify <id> <filters>\n\
  53               \filters:\n\
  54               \    -f <new file>\n\
  55               \    -t <new title>\n\
  56               \    -a +<author-add> <author-remove>\n\
  57               \    -k +<keyword-add> <keyword-remove>\n\
  58               \    -j <new journal>\n\
  59               \    -v <new volume>\n\
  60               \    -y <new year>\n\
  61               \    -p <new page-from> <new page-to>"