change mixins

[sybrandy]

On 02/16/2010 07:52 PM, sybrandy wrote:
> On 02/15/2010 05:37 PM, Pelle Månsson wrote:
>> On 02/15/2010 10:53 PM, sybrandy wrote:
>>> In short: I'm using mixins so that the person who's using the library
>>> doesn't have to put in version(DoLogging)... all over the place. By
>>> containing it in one location, I was trying to keep the code using the
>>> library cleaner.
>> void trace(string s) {
>> version (NoTrace) {
>> //do nothing
>> } else {
>> //do tracing
>> }
>> }
>>
>> trace("Stuff");
>>
>> will this not work?
>
> It will work, however I was going for "if you're not logging, why have
> the logging code in there?" Like I said, I was going for performance and
> with mixins I could ensure there was no runtime overhead with
> instantiating the class, setting up the logger, etc. when the user
> turned logging off.
>
> In this version:
>
>
> template Trace(string msg)
> {
> version (NoLogging)
> {
> }
> else
> {
> // Write to the log file...
> }
> }
>
> If NoLogging is turned on, then no code to perform the logging is even
> added to the file. It seemed to me that this was favorable to having a
> bunch of empty functions laying around. Now, if DMD was smart enough to
> eliminate empty functions, that would be great and I wouldn't have to do
> this.
>
> Regardless, I'm still all for moving the "mixin" keyword to the mixin
> declaration vs. where it's instantiated.

Well, I tried out what you guys suggested and it worked perfectly.  I 
really don't know why I thought there would still be a little overhead 
if I didn't use a mixin.  So, thanks for the help.

On a brighter note, at least I learned something new :)