[Fencommits] fenserve: make the potion editing page determine the type of the focused subexpression

[Benja Fallenstein]

Fri Jun 22 14:53:34 EEST 2007  Benja Fallenstein <benja.fallenstein at gmail.com>
  * make the potion editing page determine the type of the focused subexpression
diff -rN -u old-fenserve/fendata/Main.hs new-fenserve/fendata/Main.hs
--- old-fenserve/fendata/Main.hs	2007-06-22 14:53:42.000000000 +0300
+++ new-fenserve/fendata/Main.hs	2007-06-22 14:53:42.000000000 +0300
@@ -129,5 +129,9 @@
           ( para $ tag' "small" $
                 link (impRoot ?imp ++ "potion/" ++ showExp (removeFocus exp))
                      "<< Back"
-          , para $ renderExp exp )
+          , para $ renderExp exp
+          , hr
+          , para 
+              ( "The focused subexpression is of type '"
+              , renderType $ expType $ case getFocus exp of Just x -> x, "'" ))
   ]
diff -rN -u old-fenserve/fendata/Rendering.hs new-fenserve/fendata/Rendering.hs
--- old-fenserve/fendata/Rendering.hs	2007-06-22 14:53:42.000000000 +0300
+++ new-fenserve/fendata/Rendering.hs	2007-06-22 14:53:42.000000000 +0300
@@ -58,6 +58,12 @@
     n i = (if i<26 then "" else n (i `div` 26))
        ++ [toEnum $ fromEnum 'a' + i `mod` 26]
        
+getFocus :: Exp -> Maybe Exp
+getFocus exp = (case getFoci exp of (x:xs) -> Just x; [] -> Nothing) where
+    getFoci :: Data a => a -> [Exp]
+    getFoci = (concat . gmapQ getFoci) `extQ` expCase
+    expCase (Focus e) = [e]; expCase e = concat $ gmapQ getFoci e
+       
 focusPath p = focusPath' p . removeFocus
                  
 focusPath' :: [Int] -> GenericT