[whatwg] Non-ecmascript bindings (was Re: Serving up Theora <video> in the real world)

[Oliver Hunt]

On Jul 10, 2009, at 3:27 PM, James Graham wrote:

> Quoting Kartikaya Gupta <lists.whatwg at stakface.com>:
>
>> Really, it's not that much work to make sure the API can have   
>> bindings in other languages. As long as you can write WebIDL for  
>> it  (and provide relevant DOM feature strings wherever necessary),  
>> you  should get it for free. I would also argue that considering  
>> other  languages forces you to think more about how the API may be  
>> (ab)used  and therefore results in a better and more robust API,  
>> even if it is  never actually implemented in other languages.
>
> It's not about whether it is a lot of work; it's about whether the  
> API matches the typical programming style and feature set of the  
> target language. Where this doesn't happen (as in much of the DOM),  
> the API ends up feeling clunky and difficult to use. My experience  
> with dom-equivalent APIs that have been designed to fully take  
> advantage of the target language capabilities is that they are much  
> more pleasant to use than the equivalent DOM APIs. Indeed one of the  
> first things that most javascript libraries do is replace most of  
> the DOM  with their own API. This hardly seems like a ringing  
> endorsement of the design strategy that gave us the DOM. I don't  
> think it is sensible to optimise for the few people for whom the  
> cross-language* approach is convenient at the expense of the many or  
> whom it is bad.
>
> Sadly it seems that canPlayType is going to be another hacky-feeling  
> API because of cross-language considerations and because the  
> problems with it were not picked up soon enough :(

We added support for the updated canPlayType API to WebKit last night  
-- eg. the empty string is returned instead of "no" -- this is now  
present in the latest nightlies and seems to work for the use case we  
are looking at eg. "if (video.canPlayType(..)) ..." now succeeds if  
support is possible, and fails otherwise.

> *I idly note that DOM seems entirely unsuited to some languages so  
> it is only really cross-language to the extent that it can be  
> implemented in any language where you can mimic the style of java.

I don't buy this -- WebKit generates DOM bindings for JS, Obj-C, and C+ 
+ and has work in progress on a C binding -- while you can argue that  
these are all imperative languages and no one has made bindings for  
(say) Haskell, I cannot myself see any reason why such would not be  
possible.

--Oliver