ipynb reader/writer: use format 'ipynb' for raw cell where no format given.

According to nbformat docs, this is supposed to render in every
format.  We don't do that, but we at least preserve it as a raw
block in markdown, so you can round-trip.

2 files changed, 9 insertions, 5 deletions

diff --git a/src/Text/Pandoc/Readers/Ipynb.hs b/src/Text/Pandoc/Readers/Ipynb.hs
index 10f3a0675..04e0b1595 100644
--- a/src/Text/Pandoc/Readers/Ipynb.hs
+++ b/src/Text/Pandoc/Readers/Ipynb.hs
@@ -90,10 +90,11 @@ cellToBlocks opts lang c = do
       return $ B.divWith ("",["cell","markdown"],kvs)
              $ B.fromList bs
     Ipynb.Raw -> do
-      let format = fromMaybe "html" $ lookup "format" kvs
+      -- we use ipynb to indicate no format given (a wildcard in nbformat)
+      let format = fromMaybe "ipynb" $ lookup "format" kvs
       let format' =
             case format of
-              "text/html"       ->  "html"
+              "text/html"       -> "html"
               "text/latex"      -> "latex"
               "application/pdf" -> "latex"
               "text/markdown"   -> "markdown"
diff --git a/src/Text/Pandoc/Writers/Ipynb.hs b/src/Text/Pandoc/Writers/Ipynb.hs
index 2a95f669e..4f088f7fc 100644
--- a/src/Text/Pandoc/Writers/Ipynb.hs
+++ b/src/Text/Pandoc/Writers/Ipynb.hs
@@ -19,6 +19,7 @@ where
 import Prelude
 import Control.Monad.State
 import qualified Data.Map as M
+import Data.Char (toLower)
 import Data.Maybe (catMaybes, fromMaybe)
 import Text.Pandoc.Options
 import Text.Pandoc.Definition
@@ -136,7 +137,7 @@ extractCells opts (Div (_id,classes,kvs) xs : bs)
       case consolidateAdjacentRawBlocks xs of
         [RawBlock (Format f) raw] -> do
           let format' =
-                case f of
+                case map toLower f of
                   "html"     -> "text/html"
                   "revealjs" -> "text/html"
                   "latex"    -> "text/latex"
@@ -146,8 +147,10 @@ extractCells opts (Div (_id,classes,kvs) xs : bs)
           (Cell{
               cellType = Raw
             , cellSource = Source $ breakLines $ T.pack raw
-            , cellMetadata = M.insert "format"
-                             (Aeson.String $ T.pack format') mempty
+            , cellMetadata = if format' == "ipynb" -- means no format given
+                                then mempty
+                                else M.insert "format"
+                                       (Aeson.String $ T.pack format') mempty
             , cellAttachments = Nothing } :) <$> extractCells opts bs
         _ -> extractCells opts bs
 extractCells opts (CodeBlock (_id,classes,kvs) raw : bs)