From 994d43117231af8f9825d4df3dd3f2f6af74f8af Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Mon, 12 Dec 2016 14:15:49 +0100
Subject: [PATCH] Class:  have pure instance of openURL throw an error, for
 now.

Later we may want to include a map of URLs and mime type, bytestring
pairs in pure state to serve as a fake internet.
---
 src/Text/Pandoc/Class.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Text/Pandoc/Class.hs b/src/Text/Pandoc/Class.hs
index 9604d7c18..9c11256c8 100644
--- a/src/Text/Pandoc/Class.hs
+++ b/src/Text/Pandoc/Class.hs
@@ -396,7 +396,7 @@ instance PandocMonad PandocPure where
         modifyPureState $ \st -> st { stUniqStore = us }
         return u
       _ -> M.fail "uniq store ran out of elements"
-  openURL _ = undefined -- TODO
+  openURL _ = throwError $ PandocSomeError "Cannot open URL in PandocPure"
   readFileLazy fp = do
     fps <- getsPureState stFiles
     case infoFileContents <$> getFileInfo fp fps of