[Improve "Cannot strong:" error message
Samuel Bronson <naesten@gmail.com>**20090109202717] hunk ./E/Eval.hs 9
+import Doc.DocLike
hunk ./E/Eval.hs 97
-    eval' ds e stack= fail $ "Cannot strong: \n" ++ render (pprint (e,stack))
+    eval' ds e stack= fail . render $ text "Cannot strong:"
+                                      <$> pprint e
+                                      <$> text "With stack:"
+                                      <$> pprint stack
+                                      <$> text "And bindings for:"
+                                      <$> pprint (Map.keys ds)