Introduce initial image support

Pancake reports saved files to Emacs, Emacs inserts them into
appropriate positions if they are images; `pancake-load-images' just
sends "save" commands for all the images.

`pancake-display-hook' was added as well, so that image loading can be
requested automatically, among other things.

There is a few things to improve: currently the images don't get
sliced, there's no caching or parallelization, and no tracking of
explicitly requested images.

1 files changed, 9 insertions, 3 deletions

diff --git a/Pancake.hs b/Pancake.hs
index 74990fa..0c9db1e 100644
--- a/Pancake.hs
+++ b/Pancake.hs
@@ -179,6 +179,7 @@ goTo t u' = do
 command :: MonadIO m => Command -> StateT LoopState m ()
 command (Save (RURI uri') p) = do
   (uri, mraw) <- loadRaw uri'
+  st <- get
   case mraw of
     Nothing -> pure ()
     Just (raw, euri, _) -> liftIO $ do
@@ -202,10 +203,15 @@ command (Save (RURI uri') p) = do
           targetFileName = fromMaybe remoteFileName mTargetName
           targetPath = targetDir </> targetFileName
       e <- try $ BS.writeFile targetPath raw
-      putErrLn $ unwords $ case e of
+      case e of
         Left (err :: SomeException) ->
-          ["Failed to write", targetPath ++ ":", show err]
-        Right _ -> ["Saved", remoteURIStr, "as", targetPath]
+          putErrLn $ unwords ["Failed to write", targetPath ++ ":", show err]
+        Right () -> do
+          when (embedded st) $
+            putSexpLn [ "saved"
+                      , encodeSexpStr $ uriToString id uri' ""
+                      , encodeSexpStr targetPath]
+          putErrLn $ unwords ["Saved", remoteURIStr, "as", targetPath]
   where
     escapeURI c
       | isPathSeparator c = '-'