Null references redux

[Andrei Alexandrescu]

language_fan wrote:
> Mon, 28 Sep 2009 15:35:07 -0400, Jesse Phillips thusly wrote:
> 
>> language_fan Wrote:
>>
>>>> Now if you really want to throw some sticks into the spokes, you
>>>> would say that if the program crashes due to a null pointer, it is
>>>> still likely that the programmer will just initialize/set the value
>>>> to a "default" that still isn't valid just to get the program to
>>>> continue to run.
>>> Why should it crash in the first place? I hate crashes. You liek them?
>>> I can prove by structural induction that you do not like them when you
>>> can avoid crashes with static checking.
>> No one likes programs that crash, doesn't that mean it is an incorrect
>> behavior though?
>>
>>> Have you ever used functional languages? When you develop in Haskell or
>>> SML, how often you feel there is a good change something will be
>>> initialized to the wrong value? Can you show some statistics that show
>>> how unsafe this practice is?
>> So isn't that the question? Does/can "default" (by human or machine)
>> initialization create an incorrect state? If it does, do we continue to
>> work as if nothing was wrong or crash? I don't know how often the
>> initialization would be incorrect, but I don't think Walter is concerned
>> with it's frequency, but that it is possible.
> 
> Value types can be incorrectly initialized and nobody notices. E.g.
> 
>   int min;
> 
>   foreach(int value; list)
>     if (value < min) min = value;
> 
> Oops, you forgot to define a flag variable or initialize to int.min

You mean int.max :o).

Andrei