Org reader: undo code duplication

Some code was duplicated (copy-pasted) or placed in an inappropriate
module during the modularization refactoring.  Those functions are moved
into a `Shared` module, as was originally intended but forgotten.
Better documentation of the respective functions is a positive
side-effect.

4 files changed, 84 insertions, 55 deletions

diff --git a/pandoc.cabal b/pandoc.cabal
index 7d7250a21..0484b3293 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -398,6 +398,7 @@ Library
                    Text.Pandoc.Readers.Org.Inlines,
                    Text.Pandoc.Readers.Org.ParserState,
                    Text.Pandoc.Readers.Org.Parsing,
+                   Text.Pandoc.Readers.Org.Shared,
                    Text.Pandoc.Writers.Shared,
                    Text.Pandoc.Asciify,
                    Text.Pandoc.MIME,
diff --git a/src/Text/Pandoc/Readers/Org/Blocks.hs b/src/Text/Pandoc/Readers/Org/Blocks.hs
index 36645a356..e26beffdc 100644
--- a/src/Text/Pandoc/Readers/Org/Blocks.hs
+++ b/src/Text/Pandoc/Readers/Org/Blocks.hs
@@ -35,6 +35,9 @@ import           Text.Pandoc.Readers.Org.BlockStarts
 import           Text.Pandoc.Readers.Org.Inlines
 import           Text.Pandoc.Readers.Org.ParserState
 import           Text.Pandoc.Readers.Org.Parsing
+import           Text.Pandoc.Readers.Org.Shared
+                   ( isImageFilename, rundocBlockClass, toRundocAttrib
+                   , translateLang )
 
 import qualified Text.Pandoc.Builder as B
 import           Text.Pandoc.Builder ( Inlines, Blocks )
@@ -43,7 +46,6 @@ import           Text.Pandoc.Compat.Monoid ((<>))
 import           Text.Pandoc.Options
 import           Text.Pandoc.Shared ( compactify', compactify'DL )
 
-import           Control.Arrow ( first )
 import           Control.Monad ( foldM, guard, mzero )
 import           Data.Char ( isSpace, toLower, toUpper)
 import           Data.List ( foldl', intersperse, isPrefixOf )
@@ -314,7 +316,6 @@ codeHeaderArgs = try $ do
     else ([ pandocLang ], parameters)
  where
    hasRundocParameters = not . null
-   toRundocAttrib = first ("rundoc-" ++)
 
 switch :: OrgParser (Char, Maybe String)
 switch = try $ simpleSwitch <|> lineNumbersSwitch
@@ -323,25 +324,6 @@ switch = try $ simpleSwitch <|> lineNumbersSwitch
    lineNumbersSwitch = (\ls -> ('l', Just ls)) <$>
                        (string "-l \"" *> many1Till nonspaceChar (char '"'))
 
-translateLang :: String -> String
-translateLang "C"          = "c"
-translateLang "C++"        = "cpp"
-translateLang "emacs-lisp" = "commonlisp" -- emacs lisp is not supported
-translateLang "js"         = "javascript"
-translateLang "lisp"       = "commonlisp"
-translateLang "R"          = "r"
-translateLang "sh"         = "bash"
-translateLang "sqlite"     = "sql"
-translateLang cs = cs
-
--- | Prefix used for Rundoc classes and arguments.
-rundocPrefix :: String
-rundocPrefix = "rundoc-"
-
--- | The class-name used to mark rundoc blocks.
-rundocBlockClass :: String
-rundocBlockClass = rundocPrefix ++ "block"
-
 blockOption :: OrgParser (String, String)
 blockOption = try $ do
   argKey <- orgArgKey
diff --git a/src/Text/Pandoc/Readers/Org/Inlines.hs b/src/Text/Pandoc/Readers/Org/Inlines.hs
index 6971ca3c6..be7fc600a 100644
--- a/src/Text/Pandoc/Readers/Org/Inlines.hs
+++ b/src/Text/Pandoc/Readers/Org/Inlines.hs
@@ -30,13 +30,15 @@ module Text.Pandoc.Readers.Org.Inlines
   ( inline
   , inlines
   , addToNotesTable
-  , isImageFilename
   , linkTarget
   ) where
 
 import           Text.Pandoc.Readers.Org.BlockStarts
 import           Text.Pandoc.Readers.Org.ParserState
 import           Text.Pandoc.Readers.Org.Parsing
+import           Text.Pandoc.Readers.Org.Shared
+                   ( isImageFilename, rundocBlockClass, toRundocAttrib
+                   , translateLang )
 
 import qualified Text.Pandoc.Builder as B
 import           Text.Pandoc.Builder ( Inlines )
@@ -47,35 +49,12 @@ import           Text.Pandoc.Readers.LaTeX ( inlineCommand, rawLaTeXInline )
 import           Text.TeXMath ( readTeX, writePandoc, DisplayType(..) )
 import qualified Text.TeXMath.Readers.MathML.EntityMap as MathMLEntityMap
 
-import           Control.Arrow ( first )
 import           Control.Monad ( guard, mplus, mzero, when )
 import           Data.Char ( isAlphaNum, isSpace )
-import           Data.List ( isPrefixOf, isSuffixOf )
+import           Data.List ( isPrefixOf )
 import           Data.Maybe ( fromMaybe )
 import qualified Data.Map as M
 
--- | Prefix used for Rundoc classes and arguments.
-rundocPrefix :: String
-rundocPrefix = "rundoc-"
-
--- | The class-name used to mark rundoc blocks.
-rundocBlockClass :: String
-rundocBlockClass = rundocPrefix ++ "block"
-
-toRundocAttrib :: (String, String) -> (String, String)
-toRundocAttrib = first ("rundoc-" ++)
-
-translateLang :: String -> String
-translateLang "C"          = "c"
-translateLang "C++"        = "cpp"
-translateLang "emacs-lisp" = "commonlisp" -- emacs lisp is not supported
-translateLang "js"         = "javascript"
-translateLang "lisp"       = "commonlisp"
-translateLang "R"          = "r"
-translateLang "sh"         = "bash"
-translateLang "sqlite"     = "sql"
-translateLang cs = cs
-
 --
 -- Functions acting on the parser state
 --
@@ -405,15 +384,6 @@ cleanLinkString s =
      in all (\c -> isAlphaNum c || c `elem` (".-"::String)) scheme
           && not (null path)
 
-isImageFilename :: String -> Bool
-isImageFilename filename =
-  any (\x -> ('.':x)  `isSuffixOf` filename) imageExtensions &&
-  (any (\x -> (x++":") `isPrefixOf` filename) protocols ||
-   ':' `notElem` filename)
- where
-   imageExtensions = [ "jpeg" , "jpg" , "png" , "gif" , "svg" ]
-   protocols = [ "file", "http", "https" ]
-
 internalLink :: String -> Inlines -> F Inlines
 internalLink link title = do
   anchorB <- (link `elem`) <$> asksF orgStateAnchorIds
diff --git a/src/Text/Pandoc/Readers/Org/Shared.hs b/src/Text/Pandoc/Readers/Org/Shared.hs
new file mode 100644
index 000000000..3ba46b9e4
--- /dev/null
+++ b/src/Text/Pandoc/Readers/Org/Shared.hs
@@ -0,0 +1,76 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-
+Copyright (C) 2014-2016 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.Readers.Org.Options
+   Copyright   : Copyright (C) 2014-2016 Albert Krewinkel
+   License     : GNU GPL, version 2 or above
+
+   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
+
+Utility functions used in other Pandoc Org modules.
+-}
+module Text.Pandoc.Readers.Org.Shared
+  ( isImageFilename
+  , rundocBlockClass
+  , toRundocAttrib
+  , translateLang
+  ) where
+
+import           Control.Arrow ( first )
+import           Data.List ( isPrefixOf, isSuffixOf )
+
+
+-- | Check whether the given string looks like the path to of URL of an image.
+isImageFilename :: String -> Bool
+isImageFilename filename =
+  any (\x -> ('.':x)  `isSuffixOf` filename) imageExtensions &&
+  (any (\x -> (x++":") `isPrefixOf` filename) protocols ||
+   ':' `notElem` filename)
+ where
+   imageExtensions = [ "jpeg" , "jpg" , "png" , "gif" , "svg" ]
+   protocols = [ "file", "http", "https" ]
+
+-- | Prefix used for Rundoc classes and arguments.
+rundocPrefix :: String
+rundocPrefix = "rundoc-"
+
+-- | The class-name used to mark rundoc blocks.
+rundocBlockClass :: String
+rundocBlockClass = rundocPrefix ++ "block"
+
+-- | Prefix the name of a attribute, marking it as a code execution parameter.
+toRundocAttrib :: (String, String) -> (String, String)
+toRundocAttrib = first (rundocPrefix ++)
+
+-- | Translate from Org-mode's programming language identifiers to those used
+-- by Pandoc.  This is useful to allow for proper syntax highlighting in
+-- Pandoc output.
+translateLang :: String -> String
+translateLang cs =
+  case cs of
+    "C"          -> "c"
+    "C++"        -> "cpp"
+    "emacs-lisp" -> "commonlisp" -- emacs lisp is not supported
+    "js"         -> "javascript"
+    "lisp"       -> "commonlisp"
+    "R"          -> "r"
+    "sh"         -> "bash"
+    "sqlite"     -> "sql"
+    _            -> cs