src/Darcs/Commands/Help.lhs

   1 %  Copyright (C) 2002-2004 David Roundy
   2 %
   3 %  This program is free software; you can redistribute it and/or modify
   4 %  it under the terms of the GNU General Public License as published by
   5 %  the Free Software Foundation; either version 2, or (at your option)
   6 %  any later version.
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   8 %  This program is distributed in the hope that it will be useful,
   9 %  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 %  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 %  GNU General Public License for more details.
  12 %
  13 %  You should have received a copy of the GNU General Public License
  14 %  along with this program; see the file COPYING.  If not, write to
  15 %  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  16 %  Boston, MA 02110-1301, USA.
  17
  18 \subsection{darcs help}
  19 \label{help}
  20
  21 You could also call \verb|help| as a command.  This is equivalent to calling
  22 darcs --help.
  23 the \verb|--help| to that command.  For example, \verb|darcs help query manifest|
  24 is equivalent to \verb|darcs query manifest --help|.
  25
  26 \begin{code}
  27 module Darcs.Commands.Help ( help_cmd, command_control_list, print_version,
  28                              list_available_commands
  29                            ) where
  30 import System.Exit ( ExitCode(..), exitWith )
  31
  32 import Autoconf( darcs_version )
  33 import Darcs.Commands ( CommandControl(Command_data), DarcsCommand(..),
  34                         disambiguate_commands, CommandArgs(..),
  35                         get_command_help, extract_commands,
  36                        nodefaults,
  37                        usage )
  38 import Darcs.Arguments ( DarcsFlag(..), help_on_match )
  39 import Darcs.External ( viewDoc )
  40 import Darcs.Patch.Match ( helpOnMatchers )
  41 import Darcs.Utils ( withCurrentDirectory )
  42 import Printer ( text )
  43 import Workaround ( getCurrentDirectory )
  44 import qualified Darcs.TheCommands as TheCommands
  45 \end{code}
  46
  47 \options{help}
  48
  49 \haskell{help_description}
  50 \begin{code}
  51 help_description :: String
  52 help_description = "Display help for darcs or a single command."
  53 \end{code}
  54 \haskell{help_help}
  55
  56 \begin{code}
  57 help_help :: String
  58 help_help =
  59  "help displays usage information for darcs in general or for a single\n" ++
  60  "command (for example, darcs help query manifest).\n\n"
  61 \end{code}
  62
  63 \begin{code}
  64 help :: DarcsCommand
  65 help = DarcsCommand {command_name = "help",
  66                      command_help = help_help,
  67                      command_description = help_description,
  68                      command_extra_args = -1,
  69                      command_extra_arg_help = ["[<DARCS_COMMAND> [DARCS_SUBCOMMAND]]  "],
  70                      command_command = help_cmd,
  71                      command_prereq = \_ -> return $ Right (),
  72                      command_get_arg_possibilities = return [],
  73                      command_argdefaults = nodefaults,
  74                      command_advanced_options = [],
  75                      command_basic_options = [help_on_match]}
  76 \end{code}
  77
  78 \begin{code}
  79 help_cmd :: [DarcsFlag] -> [String] -> IO ()
  80 help_cmd opts [] =
  81     do viewDoc $ text $
  82          case () of _ | HelpOnMatch `elem` opts -> helpOnMatchers
  83                       | otherwise -> usage command_control_list
  84        exitWith $ ExitSuccess
  85
  86 help_cmd _ (cmd:args) =
  87     do let disambiguated = disambiguate_commands command_control_list cmd args
  88        case disambiguated of
  89          Left err       -> fail err
  90          Right (cmds,_) ->
  91            let msg = case cmds of
  92                      CommandOnly c       -> get_command_help Nothing  c
  93                      SuperCommandOnly c  -> get_command_help Nothing  c
  94                      SuperCommandSub c s -> get_command_help (Just c) s
  95            in viewDoc $ text msg
  96        exitWith $ ExitSuccess
  97
  98 list_available_commands :: IO ()
  99 list_available_commands =
 100     do here <- getCurrentDirectory
 101        is_valid <- sequence $ map
 102                    (\c-> withCurrentDirectory here $ (command_prereq c) [])
 103                    (extract_commands command_control_list)
 104        putStr $ unlines $ map (command_name . fst) $
 105                 filter (isRight.snd) $
 106                 zip (extract_commands command_control_list) is_valid
 107        putStrLn "--help"
 108        putStrLn "--version"
 109        putStrLn "--exact-version"
 110        putStrLn "--overview"
 111     where isRight (Right _) = True
 112           isRight _ = False
 113 \end{code}
 114
 115 \begin{code}
 116 print_version :: IO ()
 117 print_version = putStrLn $ "darcs version " ++ darcs_version
 118 \end{code}
 119
 120 \begin{code}
 121 -- avoiding a module import cycle between Help and TheCommands
 122 command_control_list :: [CommandControl]
 123 command_control_list =
 124   Command_data help : TheCommands.command_control_list
 125 \end{code}
 126