5.  Querying Event Handlers

      In addition to associating event handlers with events by means of the ``def'' primitives, several primitives exist to query the currently defined handler for a given event:

(requestdef name)
(macrodef name)
(specialdef name)
(stringdef name)
(numregdef name)
(escapedef name)
(chardef name)
(sentencedef)
(equationdef)

      Observe that the name of each primitive is derived from the name of the corresponding ``def'' primitive by exchanging the word ``def'' and the rest of the name. Each name argument is subject to the constraints described under the corresponding ``def'' primitive above. Each primitive returns whatever object has been registered as the event handler (procedure, string, symbol, character); or #f if no handler has been defined for the event.