dmd 1.046 and 2.031 releases

[Robert Jacques]

On Tue, 07 Jul 2009 03:33:24 -0400, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:
> Robert Jacques wrote:
>>  That's really cool. But I don't think that's actually happening (Or  
>> are these the bugs you're talking about?):
>>      byte x,y;
>>     short z;
>>     z = x+y;  // Error: cannot implicitly convert expression  
>> (cast(int)x + cast(int)y) of type int to short
>>      // Repeat for ubyte, bool, char, wchar and *, -, /
>
> http://d.puremagic.com/issues/show_bug.cgi?id=3147 You may want to add  
> to it.

Added. In summary, + * - / % >> >>> don't work for types 8-bits and under.  
<< is inconsistent (x<<1 errors, but x<<y compiles). All the op assigns  
(+= *= -= /= %= >>= <<= >>>=) and pre/post increments (++ --) compile  
which is maddeningly inconsistent, particularly when the spec defines ++x  
as sugar for x = x + 1, which doesn't compile.

>> And by that logic shouldn't the following happen?
>>      int x,y;
>>     int z;
>>     z = x+y;  // Error: cannot implicitly convert expression  
>> (cast(long)x + cast(long)y) of type long to int
>
> No. Int remains "special", i.e. arithmetic operations on it don't  
> automatically grow to become long.
>
>> i.e. why the massive inconsistency between byte/short and int/long?  
>> (This is particularly a pain for generic i.e. templated code)
>
> I don't find it a pain. It's a practical decision.

Andrei, I have a short vector template (think vec!(byte,3), etc) where  
I've had to wrap the majority lines of code in cast(T)( ... ), because I  
support bytes and shorts. I find that both a kludge and a pain.

>> BTW: this means byte and short are not closed under arithmetic  
>> operations, which drastically limit their usefulness.
>
> I think they shouldn't be closed because they overflow for relatively  
> small values.

Andrei, consider anyone who want to do image manipulation (or computer  
vision, video, etc). Since images are one of the few areas that use bytes  
extensively, and have to map back into themselves, they are basically  
sorry out of luck.