KEYSEQ = '<keyseq>' [ STRTERM | LISTTERM ] '</keyseq>'
KEYSEQTERM = KEYSEQ | VAR (value is KEYSEQ) | FUNCALL (return KEYSEQ)
-MARKER = '<marker>' SYMBOL '</marker>'
+MARKER = '<marker>' STRING '</marker>'
MARKERTERM = MARKER | VAR (value is MARKER) | FUNCALL (return MARKER)
-SELECTOR = '<selector>' SYMTERM '</selector>'
+SELECTOR = '<selector>' STRING '</selector>'
SELECTORTERM = SELECTOR | VAR (value is SELECTOR) | FUNCALL (return SELECTOR)
MIM-PREDEFINED