enum abuse

[Mike]

On Friday, 28 February 2014 at 11:47:35 UTC, Dicebot wrote:
> On Friday, 28 February 2014 at 11:27:31 UTC, Mike wrote:
>> I recently saw the following line of code:
>>
>> enum size = __traits(classInstanceSize, Foo);
>>
>> Why "enum"?  Is this the equivalent of "immutable auto" or 
>> something?
>>
>> Mike
>
> enum creates compile-time placement constant. It does not 
> create any symbol in resulting binary. Value of such enum gets 
> pasted straight into the context when used.
>
> Most similar thing in C terms would have been `#define size 
> __traits(classInstanceSize, Foo)`, alas from preprocessor 
> issues not present in D :)
>
> It is idiomatic D way to force compile-time evaluation of 
> expression.

Damn good explanation.  I think I'll do a pull for this in the 
docs.  Thank you!