Instantiation of objects -- create new space inmemory?

Question

If I have this:
lPerson : person = new;
lPerson.name.setValue('Martin');
lPerson.phone.setValue('2762109');
lPerson = new;
Does this second instantiation create a new copy of "lPerson" in memory?
Does it destroy the old? Does it create and destroy in the exact same
memory address?
-Martin

Answer 1

In a message dated 97-08-02 00:08:50 EDT, [email protected] (Martin
Nystrom) writes:
<< If I have this:
lPerson : person = new;
lPerson.name.setValue('Martin');
lPerson.phone.setValue('2762109');
lPerson = new;
Does this second instantiation create a new copy of "lPerson" in memory?
Does it destroy the old? Does it create and destroy in the exact same
memory address?
>>
IPerson is just an Object Reference (similar to a Pointer). Initially it
points to nothing and is considered NIL (if IPerson = nil then ...). Now you
can get the IPerson reference to point to an object either by assignment or
by instantiation.
In assignment (IPerson = anotherPerson; ) the Object reference is assigned to
point to the same Object that the assignor (?) reference points; note that it
points to the object and not the reference (in effect there are no pointers
to pointers).
Instantiation is somewhat similar. The =new( ) syntax creates an Object
instance and then the reference is assigned to point to it. So doing a
second =new( ) would create a second object instance and the reference would
be assigned to it. If the first object instance was not referenced by
anything else then you have no way of getting a handle on it. It is
considered garbage and forte will garbage collect the memory at some point.
In your example, the first IPerson object goes AWOL at the second =new( ) and
your IPerson reference is left pointing to a new 'empty' Object which is
somewhere else in memory.
Rob.