You need to ensure that Inform allocates enough space for the property
data, by putting blanks in your definition. For example, the
declaration
Object Blah "blah"
with ...,
before NULL NULL;
allocates enough space for two `before' routines, which you can update
like this:
(Blah.&before)-->0 = #r$BeforeRoutineOne;
(Blah.&before)-->1 = #r$BeforeRoutineTwo;
-- Gareth Rees