What about hash keys- are they duplicated for each object of the same type?

Yes.

Er, no. Hash keys are generally shared across all hashes, as the following shows. Using the same key for lots of objects uses less memory than a different key for each one: 
$ perl588 -e 'push @f,  bless { "foo$_",0 } for 100000..999999; system
+ "ps -flp $$"'
F S UID        PID  PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY          
+TIME CMD
0 S davem     6040 17980 81  85   0 - 43121 wait   19:05 pts/2    00:0
+0:04 perl5
$ perl588 -e 'push @f,  bless { "foo999999",0 } for 100000..999999; sy
+stem "ps -flp $$"'
F S UID        PID  PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY          
+TIME CMD
0 S davem     6045 17980 96  85   0 - 34173 wait   19:06 pts/2    00:0
+0:03 perl5
$

[download]

Dave.

In reply to Re^2: Perl Objects, Internal Representation -- How?? by dave_the_m
in thread Perl Objects, Internal Representation -- How?? by bratwiz

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