Re: C bug of the day

[jimmaureenrogers@worldnet.att.net (Jim Rogers)]

kanze@gabi-soft.fr wrote in message
news:<d6652001.0306190145.18d4a8c9@posting.google.com>...
> James Rogers <jimmaureenrogers@att.net> wrote in message
> news:<Xns939EC67E738EEjimmaureenrogers@204.127.36.1>...
> If I understand you
> correctly, in Ada, the programmer is never concerned with assignment,
as
> defined in C++: the compiler generated assignment operator generates
> code to use initialization and finalization.

This is true. In Ada assignment is designated to be an operation,
not an operator. There is no way to simply overrride the assignment
operator.

Ada controlled types provide the ability to override finalization,
as has been stated before. They also allow the programmer to
overrride initialization and "adjustment". Overriding adjustment
and initialization provides some of the capabilities of 
overriding assignment in C++.

The "adjustment" procedure is used for such things as incrementing
reference counts. The "finalize" procedure could be used to
decrement reference counts and deallocate an object when its
reference count is 0. 

The basic logic of assignment is unchanged by overriding
initialization, adjustment, and finalization. The specific order
of operations is unchanged. Ada controlled types simply provide
fine grained control over well defined steps in assignment.
Of course, initialization is also called whenever a controlled
object is created. Finalization is called whenever a controlled
object goes out of scope.

Jim Rogers

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