Implemented arguments processor.

diffr.cabal

@@ -1,5 +1,5 @@
 Name:               diffr
-Version:            0.0
+Version:            0.2
 Description:        Intelligent diff/patch tool that knows how to copy and move, has an 'r' at the end of its name.
 License:            GPL-3
 License-file:       LICENCE
@@ -8,12 +8,20 @@ Maintainer:
 Build-Type:         Simple
 Cabal-Version:      >=1.2
 
+Library
+  Build-Depends:    base >= 4
+  Hs-Source-Dirs:   src
+  Exposed-Modules:  Diffr.Util.ArgumentsProcessor
+  ghc-options:      -Wall
+
 Executable diffr
-  Main-is:          src/diffr/diff/Main.hs
+  Main-is:          Diffr/Diff/Main.hs
   Build-Depends:    base >= 4
-  ghc-options: -Wall
+  Other-Modules:    Diffr.Util.ArgumentsProcessor
+  Hs-Source-Dirs:   src
+  ghc-options:      -Wall
 
 Executable patchr
-  Main-is:          src/diffr/patch/Main.hs
+  Main-is:          src/Diffr/Patch/Main.hs
   Build-Depends:    base >= 4
-  ghc-options: -Wall
+  ghc-options:      -Wall

src/diffr/diff/Main.hs → src/Diffr/Diff/Main.hs

@@ -20,23 +20,24 @@
 
 module Main ( main ) where
 
+import Data.Char( intToDigit )
+import Diffr.Util.ArgumentsProcessor( containsHelpArgument, extractOutputFile )
 import System.Environment( getArgs )
 import System.Exit ( exitFailure, exitSuccess )
 
--- | 'main' runs the main program
+-- | 'main' runs diffr.
 main :: IO ()
 main = do
     args <- getArgs
-    if not ( 2 == length args || 4 == length args )
+    if ( containsHelpArgument args || not ( 2 == length args || 4 == length args ) )
       then do
         printUsage
         exitFailure
       else do
-        print ( length args )
+        print ( [intToDigit ( length args )]  ++ " arguments" )
+        print ( extractOutputFile args )
         exitSuccess
 
-
-
 -- | 'printUsage' prints the usage information for diffr.
 printUsage :: IO ()
 printUsage = putStrLn ( "Usage: \n" ++

src/Diffr/Util/ArgumentsProcessor.hs

@@ -0,0 +1,44 @@
+{- |
+ Module      :  Diffr.Util.ArgumentsProcessor
+ Description :  Arguments processor for diffr.
+ Since       :  0.2
+ Authors     :  William Martin
+ License     :  This file is part of diffr-h.
+
+ diffr-h is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ diffr-h is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ You should have received a copy of the GNU General Public License
+ along with diffr-h.  If not, see <http://www.gnu.org/licenses/>.
+-}
+
+module Diffr.Util.ArgumentsProcessor ( containsHelpArgument, extractOutputFile ) where
+
+import Data.Char ( toLower )
+
+-- | 'containsHelpArgument' checks if the given list of strings contains the help argument.
+containsHelpArgument :: [[Char]] -> Bool
+containsHelpArgument args = any isHelpArgument ( map ( map toLower ) args )
+
+-- | 'extractOutputFile' extracts the output file argument from a list of strings.
+extractOutputFile :: [[Char]] -> [Char]
+extractOutputFile args = case args of
+    [] -> ""
+    ("-o":[]) -> ""
+    ("-o":xs) -> head ( xs )
+    _ -> extractOutputFile ( tail args )
+
+-- | 'isHelpArgument' checks if a string is a help argument.
+isHelpArgument :: [Char] -> Bool
+isHelpArgument arg = case arg of
+    [] -> False
+    ('-':[]) -> False
+    ('-':xs) -> isHelpArgument( xs )
+    "help" -> True
+    _ -> False