Aaron,
> That in both cases the object is modifiable yet only the
> 'var' case allows the reference
> pointer itself to be changed (since the reference pointer is
> passed by reference).
I guess this can be confusing, especially for C++ programmers. In Delphi,
there is no such thing as an object instance variable. There are only
object references, which *ARE* pointers. So, no matter what you do, only
pointers are involved. In C++, passing an object instance by value invokes
the copy constructor. In Delphi, only the pointer is copied.
> > In procedure A, you are passing a reference by value, and
> in procedure B,
> > you are passing a reference by reference (ie. pointer to
> pointer). Where is
> > it that Delphi lies? Bear in mind that all objects in
> Delphi are references
> > (ie pointers).
> Delphi is not doing an offset when accessing via the '.'
> operator it is in fact doing '^.'
> hiding the fact that the is a dereference involved. The lie
> is that an instance declaration
> is only a pointer declaration...
This is purely syntactical and the help explains this. In BP7 (old way),
you always do a '^.', but Borland changed that to '.' in Delphi. Its not a
lie. It is the way Delphi has been designed, and IMHO, is better than the
'^.' construct, and certainly better than C++'s '.' and '->' constructs. I
guess the only down-side to using '.' is that it is used to denote fields in
records, thus making its use inconsistent. However, IMHO, OO programming
ought not to use records anyway.
> Do does delphi handle it's dynamic array passing when passed
> as a typed parameter,
> does delphi pass only the reference or does it still pass the
> entire array as value.
Hmmm. I would think that Delphi handles dynamic arrays like strings, but
I'm not quite sure, I'll need to check this out ... one free weekend :).
The AnsiString example can be used for this. Convert it into dynamic
arrays, and check out the pointer values. Should give you a clue as to what
Delphi is doing. Will also need to look at the assembly generated.
Regards,
Dennis.
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