Implicit integer casting

[Andrei Alexandrescu]

On 3/18/12 4:12 PM, James Miller wrote:
> On 19 March 2012 08:53, Andrej Mitrovic<andrej.mitrovich at gmail.com>  wrote:
>> Another classic which fails to compile is:
>>
>> import std.random;
>> ubyte c = uniform(0, 256);
>>
>> In the call uniform returns a number anywhere from 0 to and including
>> 255, which can fit perfectly in a ubyte. But I have to use a cast
>> (which is error-prone if I change the right interval), or use a
>> to!ubyte call (which is verbose). Granted for simple-purpose random
>> number generation a cast might be safe..
>
> Another thing I have noticed, is that that compared to a cast,
> to!<type>  is incredibly slow. Most of the time it doesn't matter, but
> I was doing some work with noise generation, and found that casting
> the floats to integers was an order of magnitude faster than using
> to!int.

There's a check involved, and possibly inlining doesn't make it for 
whatever reason.

Andrei