[Tutor] destructor methods

[Lloyd Kvam]

C++ puts responsibility for heap memory management on the programmer.  new
will grab some memory and del will release.

In converting to Python:
	x = new Class;	==>	x = Class()
	(that c++ code is from memory.  It may be slightly off)
The del statements can be discarded.

__del__ exists for odd situations.  One example, if your class creates
doubly linked lists, you could have:
	a.next = b
	b.prior = a
	del a; del b
Python's old garbager collect will NOT collect this memory because those
two deleted each reference each other.  I beleive there are PEP's to improve
this, but don't know where they stand.  These deletions also break the list!
You would use __del__ to come up with logic to handle these kinds of cases
AND also protect the linked list so that deletions didn't break the list.

Timothy Wilson wrote:

> On Sat, 1 Dec 2001, Andrew Wilkins wrote:
> 
> 
>>When defining a class, you can define a method called __del__ to handle what
>>happens in the deletion, so it has the desired effect. Look for more in
>>"3.3.1 Basic Customisation" in the Python Reference Manual.
>>
> 
> So is there a performance benefit to explicitly calling __del__?
> 
> -Tim
> 
> --
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Lloyd Kvam
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