try/catch idiom in std.datetime

[Shammah Chancellor]

On 2013-11-22 02:13:42 +0000, Jesse Phillips said:

> On Friday, 22 November 2013 at 01:49:11 UTC, Shammah Chancellor wrote:
>> On 2013-11-18 06:32:46 +0000, Andrei Alexandrescu said:
>>> 
>>> 1. Fix scope(failure) and then use it.
>>> 
>>> Andrei
>> 
>> Huh?  Scope failure has no purpose here.  It does not CATCH the 
>> exception and prevent it from bubbling up the call chain.    Try/catch 
>> does do this.
>> 
>> -Shammah
> 
> If the code is:
> 
>      scope(failure) assert(0);
> 
> Then it is a statement that the function doesn't throw. So there isn't 
> a need to catch the exception, it is merely a way to state to the 
> compiler "I've verified I know what I'm talking about and this function 
> really doesn't ever throw."
> 
> Right now just having scope(failure) in the body is making this 
> statement, and that is wrong.

Scope failure blocks should not be able to raise errors, or return 
except "out the end".