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.

1 files changed, 3 insertions, 2 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"