Lua modules: make a Haskell module for each Lua module

Definitions for the `pandoc.mediabag` modules are moved to a separate
Haskell module.

Change: minor

3 files changed, 112 insertions, 74 deletions

diff --git a/src/Text/Pandoc/Lua/Module/MediaBag.hs b/src/Text/Pandoc/Lua/Module/MediaBag.hs
new file mode 100644
index 000000000..33c441c99
--- /dev/null
+++ b/src/Text/Pandoc/Lua/Module/MediaBag.hs
@@ -0,0 +1,108 @@
+{-
+Copyright © 2017 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
+
+This program 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 2 of the License, or
+(at your option) any later version.
+
+This program 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 this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+-}
+{- |
+   Module      : Text.Pandoc.Lua.Module.MediaBag
+   Copyright   : Copyright © 2017 Albert Krewinkel
+   License     : GNU GPL, version 2 or above
+
+   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
+   Stability   : alpha
+
+The lua module @pandoc.mediabag@.
+-}
+module Text.Pandoc.Lua.Module.MediaBag
+  ( pushModule
+  ) where
+
+import Control.Monad (zipWithM_)
+import Data.IORef (IORef, modifyIORef', readIORef)
+import Data.Maybe (fromMaybe)
+import Foreign.Lua (Lua, NumResults, liftIO)
+import Text.Pandoc.Class (CommonState (..), fetchItem, putCommonState,
+                          runIOorExplode, setMediaBag)
+import Text.Pandoc.Lua.StackInstances ()
+import Text.Pandoc.Lua.Util (OrNil (toMaybe), addFunction)
+import Text.Pandoc.MIME (MimeType)
+
+import qualified Data.ByteString.Lazy as BL
+import qualified Foreign.Lua as Lua
+import qualified Text.Pandoc.MediaBag as MB
+
+--
+-- MediaBag submodule
+--
+pushModule :: CommonState -> IORef MB.MediaBag -> Lua NumResults
+pushModule commonState mediaBagRef = do
+  Lua.newtable
+  addFunction "insert" (insertMediaFn mediaBagRef)
+  addFunction "lookup" (lookupMediaFn mediaBagRef)
+  addFunction "list" (mediaDirectoryFn mediaBagRef)
+  addFunction "fetch" (fetch commonState mediaBagRef)
+  return 1
+
+insertMediaFn :: IORef MB.MediaBag
+              -> FilePath
+              -> OrNil MimeType
+              -> BL.ByteString
+              -> Lua NumResults
+insertMediaFn mbRef fp nilOrMime contents = do
+  liftIO . modifyIORef' mbRef $
+    MB.insertMedia fp (toMaybe nilOrMime) contents
+  return 0
+
+lookupMediaFn :: IORef MB.MediaBag
+              -> FilePath
+              -> Lua NumResults
+lookupMediaFn mbRef fp = do
+  res <- MB.lookupMedia fp <$> liftIO (readIORef mbRef)
+  case res of
+    Nothing -> Lua.pushnil *> return 1
+    Just (mimeType, contents) -> do
+      Lua.push mimeType
+      Lua.push contents
+      return 2
+
+mediaDirectoryFn :: IORef MB.MediaBag
+                 -> Lua NumResults
+mediaDirectoryFn mbRef = do
+  dirContents <- MB.mediaDirectory <$> liftIO (readIORef mbRef)
+  Lua.newtable
+  zipWithM_ addEntry [1..] dirContents
+  return 1
+ where
+  addEntry :: Int -> (FilePath, MimeType, Int) -> Lua ()
+  addEntry idx (fp, mimeType, contentLength) = do
+    Lua.newtable
+    Lua.push "path" *> Lua.push fp *> Lua.rawset (-3)
+    Lua.push "type" *> Lua.push mimeType *> Lua.rawset (-3)
+    Lua.push "length" *> Lua.push contentLength *> Lua.rawset (-3)
+    Lua.rawseti (-2) idx
+
+fetch :: CommonState
+      -> IORef MB.MediaBag
+      -> String
+      -> Lua NumResults
+fetch commonState mbRef src = do
+  mediaBag <- liftIO $ readIORef mbRef
+  (bs, mimeType) <- liftIO . runIOorExplode $ do
+    putCommonState commonState
+    setMediaBag mediaBag
+    fetchItem src
+  Lua.push $ fromMaybe "" mimeType
+  Lua.push bs
+  return 2 -- returns 2 values: contents, mimetype
diff --git a/src/Text/Pandoc/Lua/Module/Pandoc.hs b/src/Text/Pandoc/Lua/Module/Pandoc.hs
index 5e00a9252..ed80b9715 100644
--- a/src/Text/Pandoc/Lua/Module/Pandoc.hs
+++ b/src/Text/Pandoc/Lua/Module/Pandoc.hs
@@ -28,26 +28,22 @@ Pandoc module for lua.
 -}
 module Text.Pandoc.Lua.Module.Pandoc
   ( pushModule
-  , pushMediaBagModule
   ) where
 
-import Control.Monad (when, zipWithM_)
+import Control.Monad (when)
 import Data.Default (Default (..))
 import Data.Digest.Pure.SHA (sha1, showDigest)
-import Data.IORef (IORef, modifyIORef', readIORef)
 import Data.Maybe (fromMaybe)
 import Data.Text (pack)
 import Foreign.Lua (ToLuaStack, FromLuaStack, Lua, NumResults, liftIO)
 import System.Exit (ExitCode (..))
-import Text.Pandoc.Class (CommonState (..), fetchItem, putCommonState,
-                          runIO, runIOorExplode, setMediaBag)
+import Text.Pandoc.Class (runIO)
 import Text.Pandoc.Definition (Block, Inline)
 import Text.Pandoc.Lua.Filter (walkInlines, walkBlocks, LuaFilter)
 import Text.Pandoc.Lua.StackInstances ()
 import Text.Pandoc.Lua.Util (OrNil (toMaybe), addFunction, addValue,
                              loadScriptFromDataDir, raiseError)
 import Text.Pandoc.Walk (Walkable)
-import Text.Pandoc.MIME (MimeType)
 import Text.Pandoc.Options (ReaderOptions (readerExtensions))
 import Text.Pandoc.Process (pipeProcess)
 import Text.Pandoc.Readers (Reader (..), getReader)
@@ -55,7 +51,6 @@ import Text.Pandoc.Readers (Reader (..), getReader)
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.ByteString.Lazy.Char8 as BSL
 import qualified Foreign.Lua as Lua
-import qualified Text.Pandoc.MediaBag as MB
 
 -- | Push the "pandoc" on the lua stack. Requires the `list` module to be
 -- loaded.
@@ -93,18 +88,6 @@ readDoc content formatSpecOrNil = do
             Left s   -> raiseError (show s)              -- error while reading
         _  -> raiseError "Only string formats are supported at the moment."
 
---
--- MediaBag submodule
---
-pushMediaBagModule :: CommonState -> IORef MB.MediaBag -> Lua NumResults
-pushMediaBagModule commonState mediaBagRef = do
-  Lua.newtable
-  addFunction "insert" (insertMediaFn mediaBagRef)
-  addFunction "lookup" (lookupMediaFn mediaBagRef)
-  addFunction "list" (mediaDirectoryFn mediaBagRef)
-  addFunction "fetch" (fetch commonState mediaBagRef)
-  return 1
-
 sha1HashFn :: BL.ByteString
            -> Lua NumResults
 sha1HashFn contents = do
@@ -158,56 +141,3 @@ instance ToLuaStack PipeError where
           , BSL.pack "): "
           , if output == mempty then BSL.pack "<no output>" else output
           ]
--- end: pipe
-
-insertMediaFn :: IORef MB.MediaBag
-              -> FilePath
-              -> OrNil MimeType
-              -> BL.ByteString
-              -> Lua NumResults
-insertMediaFn mbRef fp nilOrMime contents = do
-  liftIO . modifyIORef' mbRef $
-    MB.insertMedia fp (toMaybe nilOrMime) contents
-  return 0
-
-lookupMediaFn :: IORef MB.MediaBag
-              -> FilePath
-              -> Lua NumResults
-lookupMediaFn mbRef fp = do
-  res <- MB.lookupMedia fp <$> liftIO (readIORef mbRef)
-  case res of
-    Nothing -> Lua.pushnil *> return 1
-    Just (mimeType, contents) -> do
-      Lua.push mimeType
-      Lua.push contents
-      return 2
-
-mediaDirectoryFn :: IORef MB.MediaBag
-                 -> Lua NumResults
-mediaDirectoryFn mbRef = do
-  dirContents <- MB.mediaDirectory <$> liftIO (readIORef mbRef)
-  Lua.newtable
-  zipWithM_ addEntry [1..] dirContents
-  return 1
- where
-  addEntry :: Int -> (FilePath, MimeType, Int) -> Lua ()
-  addEntry idx (fp, mimeType, contentLength) = do
-    Lua.newtable
-    Lua.push "path" *> Lua.push fp *> Lua.rawset (-3)
-    Lua.push "type" *> Lua.push mimeType *> Lua.rawset (-3)
-    Lua.push "length" *> Lua.push contentLength *> Lua.rawset (-3)
-    Lua.rawseti (-2) idx
-
-fetch :: CommonState
-      -> IORef MB.MediaBag
-      -> String
-      -> Lua NumResults
-fetch commonState mbRef src = do
-  mediaBag <- liftIO $ readIORef mbRef
-  (bs, mimeType) <- liftIO . runIOorExplode $ do
-    putCommonState commonState
-    setMediaBag mediaBag
-    fetchItem src
-  Lua.push $ fromMaybe "" mimeType
-  Lua.push bs
-  return 2 -- returns 2 values: contents, mimetype
diff --git a/src/Text/Pandoc/Lua/Packages.hs b/src/Text/Pandoc/Lua/Packages.hs
index e9173739f..03847c979 100644
--- a/src/Text/Pandoc/Lua/Packages.hs
+++ b/src/Text/Pandoc/Lua/Packages.hs
@@ -38,11 +38,11 @@ import Data.IORef (IORef)
 import Foreign.Lua (Lua, NumResults, liftIO)
 import Text.Pandoc.Class (CommonState, readDataFile, runIO, setUserDataDir)
 import Text.Pandoc.MediaBag (MediaBag)
-import Text.Pandoc.Lua.Module.Pandoc (pushMediaBagModule)
 import Text.Pandoc.Lua.Util (dostring')
 
 import qualified Foreign.Lua as Lua
 import Text.Pandoc.Lua.Module.Pandoc as Pandoc
+import Text.Pandoc.Lua.Module.MediaBag as MediaBag
 
 -- | Parameters used to create lua packages/modules.
 data LuaPackageParams = LuaPackageParams
@@ -76,7 +76,7 @@ pandocPackageSearcher luaPkgParams pkgName =
                          in pushWrappedHsFun (Pandoc.pushModule datadir)
     "pandoc.mediabag" -> let st    = luaPkgCommonState luaPkgParams
                              mbRef = luaPkgMediaBag luaPkgParams
-                         in pushWrappedHsFun (pushMediaBagModule st mbRef)
+                         in pushWrappedHsFun (MediaBag.pushModule st mbRef)
     _ -> searchPureLuaLoader
  where
   pushWrappedHsFun f = do