try/catch idiom in std.datetime

[Dmitry Olshansky]

19-Nov-2013 02:49, Walter Bright пишет:
> On 11/18/2013 2:37 PM, Andrei Alexandrescu wrote:
>> On 11/18/13 1:50 PM, Walter Bright wrote:
>>> I believe this is solving the problem in the wrong place. The function
>>> being called should not be throwing, and should be defined as not
>>> throwing. See my other posts in this thread on the topic.
>>
>> I think a stance of unceremoniously halting the program upon passing
>> the wrong
>> parameters to a standard library function is a bit excessive.
>
> Dang, I gotta argue this with you too? :-)
>
> Forget the philosophical argument for the moment and let's try a
> pragmatic one - code that doesn't check its arguments and doesn't throw
> is going to inline better, run faster, and be smaller. To have a high
> performance language, we have to have this.
>
> This is why we have a -release switch: so we can run with or without
> checking the arguments for bugs.
>
> Input data validation is where exceptions come in. Those are relatively
> rare compared with processing validated data, and so separating out the
> slow data validation path from the validated high speed path makes
> pragmatic sense.
>
> Rejecting this approach throws (!) out the whole concept of contract
> programming.
>

There is a whole class of functions where validation is ~ the same 
amount of work as scrubbing the input. Do I need to provide an example 
of parser? :)

-- 
Dmitry Olshansky