Added Text.Pandoc.Compat.TagSoupEntity.

This allows pandoc to compile with tagsoup 0.13.x.
Thanks to Dirk Ullrich for the patch.

pandoc.cabal

@@ -253,7 +253,7 @@ Library
                  citeproc-hs >= 0.3.7 && < 0.4,
                  pandoc-types >= 1.12 && < 1.13,
                  aeson >= 0.6 && < 0.7,
-                 tagsoup >= 0.12.5 && < 0.13,
+                 tagsoup >= 0.12.5 && < 0.14,
                  base64-bytestring >= 0.1 && < 1.1,
                  zlib >= 0.5 && < 0.6,
                  highlighting-kate >= 0.5.5 && < 0.6,
@@ -336,6 +336,7 @@ Library
                    Text.Pandoc.Slides,
                    Text.Pandoc.Highlighting,
                    Text.Pandoc.Compat.Monoid,
+                   Text.Pandoc.Compat.TagSoupEntity,
                    Paths_pandoc
 
   Buildable:       True

src/Text/Pandoc/Compat/TagSoupEntity.hs

@@ -0,0 +1,15 @@
+{-# LANGUAGE CPP #-}
+module Text.Pandoc.Compat.TagSoupEntity (lookupEntity
+                          ) where
+
+import qualified Text.HTML.TagSoup.Entity as TE
+
+lookupEntity :: String -> Maybe Char
+#if MIN_VERSION_tagsoup(0,13,0)
+lookupEntity = str2chr . TE.lookupEntity
+  where str2chr :: Maybe String -> Maybe Char
+        str2chr (Just [c]) = Just c
+        str2chr _ = Nothing
+#else
+lookupEntity = TE.lookupEntity
+#endif

src/Text/Pandoc/Parsing.hs

@@ -161,7 +161,7 @@ import Data.List ( intercalate, transpose )
 import Text.Pandoc.Shared
 import qualified Data.Map as M
 import Text.TeXMath.Macros (applyMacros, Macro, parseMacroDefinitions)
-import Text.HTML.TagSoup.Entity ( lookupEntity )
+import Text.Pandoc.Compat.TagSoupEntity ( lookupEntity )
 import Data.Default
 import qualified Data.Set as Set
 import Control.Monad.Reader

src/Text/Pandoc/Readers/DocBook.hs

@@ -4,7 +4,7 @@ import Text.Pandoc.Options
 import Text.Pandoc.Definition
 import Text.Pandoc.Builder
 import Text.XML.Light
-import Text.HTML.TagSoup.Entity (lookupEntity)
+import Text.Pandoc.Compat.TagSoupEntity (lookupEntity)
 import Data.Generics
 import Data.Monoid
 import Data.Char (isSpace)

src/Text/Pandoc/Readers/OPML.hs

@@ -6,7 +6,7 @@ import Text.Pandoc.Builder
 import Text.Pandoc.Readers.HTML (readHtml)
 import Text.Pandoc.Readers.Markdown (readMarkdown)
 import Text.XML.Light
-import Text.HTML.TagSoup.Entity (lookupEntity)
+import Text.Pandoc.Compat.TagSoupEntity (lookupEntity)
 import Data.Generics
 import Data.Monoid
 import Control.Monad.State

src/Text/Pandoc/XML.hs

@@ -38,7 +38,7 @@ module Text.Pandoc.XML ( escapeCharForXML,
 
 import Text.Pandoc.Pretty
 import Data.Char (ord, isAscii, isSpace)
-import Text.HTML.TagSoup.Entity (lookupEntity)
+import Text.Pandoc.Compat.TagSoupEntity (lookupEntity)
 
 -- | Escape one character as needed for XML.
 escapeCharForXML :: Char -> String