Null references (oh no, not again!)

[Georg Wrede]

bearophile wrote:
> Georg Wrede:
> 
> Thank you for your interesting notes on such aviation topics.
> 
>> Contract Programming can be viewed as checklists on the micro
>> level. When you call a function, it goes through a list of things
>> to check before actually doing its job.
> 
> In D such contracts are usually used during training flights only, in
> the real flight such check lists aren't used anymore :-)

Excellent point! That's why we have input validation. :-)

And a good implementation validates /all/ data and other input to the 
program. It's like not only closing, but locking every door and window 
before you leave home.

Some people should have a checklist for it (I know I do), too. Same with 
input validation. Leave one entrypoint unchecked, and that's where the 
storm comes in, guaranteed.