[dojo-contributors] Improved mixin semantics

Scott J. Miles sjmiles at turboajax.com
Wed Aug 8 19:11:48 EDT 2007

Should be mostly better now, as of [10032]. Sorry about that.

Note that Dijit is throwing deprecation warnings because of declare 
syntax. I will fix those once I get a sense that the new declare isn't 
breaking something else.

Scott J. Miles
TurboAjax Group

Scott J. Miles wrote:
> Argh, I may have broken Dijit with this commit. Mea culpa. I'm on it.
> Regards,
> Scott J. Miles
> TurboAjax Group
> http://www.turboajax.com
> Scott J. Miles wrote:
>> In [10026] I've committed a refactored declare.js that has improved, 
>> hopefully robust, mixin semantics.
>> "inherited" should now work inside of mixin classes, and to travel into 
>> and out of mixin trees.
>> The basic syntax for inherited is like so:
>> dojo.declare("bar", [base, mixin, mixin2], {
>>    foo: function() {
>>      this.inherited("foo", arguments);
>>    }
>> });
>> Note that the first argument must be the name of the function and the 
>> second argument must literally be 'arguments'. More on this below.
>> The inherited call will seek ancestral 'foo' in right-to-left order. 
>> Iow, first it looks in mixin2 (and up through it's ancestry) and then 
>> into mixin, and finally base.
>> I added a basic test in the test suite, hopefully you guys can bang on 
>> it and see if there are any flaws (ahem, see where the flaws are). 
>> Internally we've thrown some crazy structures at it and so far so good.
>> Wrt to the signature, I realize that it's odd, but it makes the magic 
>> happen.
>> Note that in Dean's Base2 he's solved this problem by RegEx'ing method 
>> code to detect the superclass call and then wrapping methods in closures 
>> as needed to setup the necessary info. This is clever as usual and makes 
>> most of the work into one-time preprocessing.
>> The benefit of declare is that it works regardless of how a particular 
>> method got into your class. That is, you can poke methods directly into 
>> prototypes or instances and 'inherited' should still work properly.
>> This was all a lot of work, so if you hate declare in general, or simply 
>> would prefer some other tack, please start a new thread and give your 
>> objective reasoning. I will be grateful as that will keep my head from 
>> exploding. :)
>> Regards,
>> Scott J. Miles
>> TurboAjax Group
>> http://www.turboajax.com

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