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Re: Point of Extensibility

From: Henri Sivonen <hsivonen@iki.fi>
Date: Thu, 3 Apr 2008 18:03:12 +0300
Cc: public-html@w3.org
Message-Id: <4B3642BC-3C17-4DF2-B21F-D5CE8D0CC91E@iki.fi>
To: Doug Schepers <schepers@w3.org>

On Apr 3, 2008, at 17:32, Doug Schepers wrote:
> 2) Implied:
> <p>stuff
> <svg xmlns="http://www.w3.org/2000/svg">
>  <circle />
> </svg>

Once you allow this, the whole <ext> element becomes pointless.

> Tree:
> |P
>   |EXT
>     |FALLBACK
>     |svg xmlns="http://www.w3.org/2000/svg"
>       |circle

That violates one of our design principles:
http://www.w3.org/TR/html-design-principles/#dom-consistency

And not even for a good reason once you allow the omission of the  
<ext> tag in source.

> Two advantages to explicitly using <ext>, however:
>
> * Compatible with Henri's general solution, but with the added  
> benefit of the ability to supply a rich fallback.

Without <ext>, SVG <desc> could be appropriated for fallback. If  
that's objectionable, a <fallback> element could be allowed where SVG  
now allows <desc>.

> * Incredibly unlikely to break any content... there may be content  
> out there like #2, but unlikely to be any like #1; you could think  
> of the <ext> as a sort of "early warning" to browsers that a known  
> "insertion mode" is about to follow.


I'm not at all convinced that a wrapper named <ext> would solve  
problems that a wrapper named <svg> wouldn't.

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Thursday, 3 April 2008 15:03:56 UTC

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