Added main method/module.

2 files changed, 35 insertions, 1 deletions

diff --git a/hakyll.cabal b/hakyll.cabal
index 0f6d98e..ed1dfb4 100644
--- a/hakyll.cabal
+++ b/hakyll.cabal
@@ -20,7 +20,8 @@ library
   hs-source-dirs: src/
   build-depends:   base >= 4 && < 5, template, filepath, directory, containers, bytestring,
                    pandoc >= 1, regex-compat
-  exposed-modules: Text.Hakyll.Render
+  exposed-modules: Text.Hakyll
+                   Text.Hakyll.Render
                    Text.Hakyll.Renderable
                    Text.Hakyll.Renderables
                    Text.Hakyll.CompressCSS
diff --git a/src/Text/Hakyll.hs b/src/Text/Hakyll.hs
new file mode 100644
index 0000000..6e85907
--- /dev/null
+++ b/src/Text/Hakyll.hs
@@ -0,0 +1,33 @@
+module Text.Hakyll
+    ( hakyll
+    ) where
+
+import System.Environment (getArgs, getProgName)
+import System.Directory (doesDirectoryExist, removeDirectoryRecursive)
+
+-- | Main function to run hakyll.
+hakyll :: IO () -> IO ()
+hakyll action = do
+    args <- getArgs
+    case args of []          -> action
+                 ["--clean"] -> clean
+                 _           -> showHelp
+
+clean :: IO ()
+clean = do remove' "_cache"
+           remove' "_site"
+    where remove' dir = do exists <- doesDirectoryExist dir
+                           if exists then removeDirectoryRecursive dir
+                                     else return ()
+
+-- | Show usage information.
+showHelp :: IO ()
+showHelp = do
+    name <- getProgName
+    putStrLn $  "This is a hakyll site generator program. You should always run\n"
+             ++ "it from the project root directory.\n"
+             ++ "\n"
+             ++ "Usage:\n"
+             ++ name ++ "           Generate the site.\n"
+             ++ name ++ " --clean   Clean up and remove cache.\n"
+             ++ name ++ " --help    Show this message.\n"