+ Safety question before deleting a grammar
+ Check identifier syntax
+ Allow lincat for deleted cat to be deleted
+ Allow lin for deleted fun to be deleted
+ Apply category alpha conversion in concrete syntax
+ Remove a concrete syntax
+ Apply function alpha conversion in concrete syntax
+ Change lhs of lins when function type is changed

- Allow languages other than the ones in the given list to be added
+ Export as plain text
- Allow definitions to be reordered

+ 1. possibility to compile the grammar set, returning a URL to a translator app
- 2. possibility to import modules - both resource libraries and user's own
     auxiliaries
- 3. possibility to upload own modules
+ 4. access to the created files in an on-line shell (making testing possible)
- 5. rule-to-rule type checking and guidance (e.g. with library oper
     suggestions)
-    Try grammars in the Translation Quiz

+ compile only the uploaded grammar even if other grammars are present
+ 'flags startcat' is needed for grammars with only one category (since the
   default startcat is S, even if it doesn't exist)

- Bug! After adding a 2nd def of a fun with a different type and then deleting
  the old fun, the corresponding lin will have the wrong lhs.

- Bug! The startcat menu shows the first category by default, but the startcat
  flag is actually not set until a selection is made from the menu.