Checked oveflows in C#

[Denis Koroskin]

On Mon, 26 Jan 2009 20:54:38 +0300, Nick Sabalausky <a at a.a> wrote:

> "bearophile" <bearophileHUGS at lycos.com> wrote in message
> news:glk5pj$22rt$1 at digitalmars.com...
>> It seems one group of ideas and syntax I did suggest for D weren't so
>> Krazy, after all. I have just found that they can be seen almost equal  
>> in
>> C#.
>>
>> You can read something about them here:
>> http://msdn.microsoft.com/en-us/library/a569z7k8.aspx
>>
>> There is the checked/unchecked keyword that can be used to denote a  
>> block
>> of code:
>>
>> checked {
>>    z = x * y;
>> }
>>
>> unchecked {
>>    z = x * y;
>> }
>>
>> Or even just an expression:
>> z = checked(a + b);
>>
>> z = unchecked(a + b);
>>
>> Beside that, you also have a global compiler flag that activates or
>> disables the oveflow checks globally. So if you activate them globally,
>> you can disable them locally, and if you disable them globally you can
>> activate them locally.
>>
>> As you may remember, I did invent a similar design for D, but:
>> - I didn't invent the ability to activate/disable such checks for a  
>> single
>> expression. I am not sure how much this can be useful.
>> - I did invent a syntax to tell what controls to perform, for example:
>> safe(overflow, bounds, ...) { ... }
>> unsafe(overflow, bounds, ...) { ... }
>>
>> Note that for non-English people it's not easy to write the keywords
>> checked/unchecked, that's why I think safe()/unsafe() words are better.
>>
>
> Agreed. I've felt for a while that D should copy C#'s checked/unchecked
> system (maybe with your extensions, too).
>
>

I agree. I have proposed the same a few times in the past.
'checked' can be implemented in a library (to some degree) but a full-fledged solution needs compiler support.