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RE: algorithmic normative conformance requirements, design principles, etc.

From: Larry Masinter <masinter@adobe.com>
Date: Wed, 27 May 2009 18:28:10 -0700
To: Boris Zbarsky <bzbarsky@MIT.EDU>
CC: HTML WG <public-html@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118CD95E774@nambx04.corp.adobe.com>
But in fact there is no way to determine if image.width
and image.height are simultaneously available, because
'available' is dynamic. Any program of the form

  if (image.width != 0) { ... something using image.height ...
                          which assumes image.height is non-zero ...}

will not always function properly, if the image becomes
unavailable between the time image.width is computed
and when image.height is accessed, because images can
become "unavailable", because of network congestion, 
server timeout, delay, etc.

My original point was that this was an instance of
using algorithmic specification rather than using
language constraint specification. I think there are
numerous examples of that -- that it is endemic,
but I've only provided two examples. In order to make
the point,  I believe that I can take a random page
and discover similar difficulties everywhere in the

Perhaps you'd like to find some part of the spec which
*isn't* ambiguous or poorly specified in this way?
Some single example / page / section which you think
is completely specified both from a user and client
point of view?

That would be interesting... 


-----Original Message-----
From: Boris Zbarsky [mailto:bzbarsky@MIT.EDU] 
Sent: Wednesday, May 27, 2009 6:13 PM
To: Larry Masinter
Subject: Re: algorithmic normative conformance requirements, design principles, etc.

Larry Masinter wrote:
> I was talking specifically about the question of whether
> image.width and image.height are simultaneously available,
> and the assertion that because some authors might depend on
> it

Not might, do.  If it were a might, the situation might have been 
somewhat different.

> the specification needed to require implementations
> to make them available

Right.  Implementations that want to correctly render existing webpages 
need to do this.

> and the inconsistency of that requirement
> with asynchronous processing.

Yep.  Sad, but true.  There are all sorts of requirements imposed on UAs 
and hence on the spec by legacy content; this is one of them.


Received on Thursday, 28 May 2009 01:28:58 UTC

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