DMD 1.027 and 2.011 releases

[Charles D Hixson]

eao197 wrote:
> On Thu, 28 Feb 2008 19:34:45 +0300, Russell Lewis 
> <webmaster at villagersonline.com> wrote:
> 
>>>  It is not necessary to catch AssertError. Sometimes it is necessary 
>>> to catch any error. For example, in a HTTP-server you could start 
>>> processing of a new request and catch different kinds of errors to 
>>> make appropriate response:
>>
>> I agree that a web server needs to post an appropriate response.  But 
>> if an assert() has failed, you don't know if the failure is in your 
...
> 
> For example, SMS body in 140 bytes long. 7-bit message could be up to 
> 160 symbols, packed into 140 bytes SMS body. You could have 7-bit 
> message packing functions with precondition:
> 
> byte[] pack7bitMessage( byte[] message )
>   in { assert( message.length <= 160 ); }
>   body { ... }
> 
...

I think you are misunderstanding the purpose of assert and of 
other conditions.  Remember, these statements will be stripped 
out of the code when it is compiled for release.  As such, 
they should only be used to detect conditions which are 
genuine errors.  The reason that they might be cause would be 
so that the actual error could be raised from the location 
where the error is generated, rather than from where it was 
detected.

In Other Words:  Don't use contracts as a substitute for 
conditionals, even if the conditional *would* raise an 
exception.  They aren't the same concept.

Now I'll grant that in some languages the two concepts are 
fused, and conditionals are constrained to do double duty as 
exceptions.  Even in those languages, however, there is often 
a flag that will cause assertions to become null statements 
when compiled with optimization (or without debugging turned on).
[N.B.:  The prior paragraph is based on certain dialects of C 
or C++ that are over a decade old now.  It may not apply to 
currently extant compilers.]