W3C home > Mailing lists > Public > public-html@w3.org > March 2009

Re: Draft text for summary attribute definition

From: Philip TAYLOR <P.Taylor@Rhul.Ac.Uk>
Date: Sun, 01 Mar 2009 15:10:48 +0000
Message-ID: <49AAA578.70301@Rhul.Ac.Uk>
To: public-html@w3.org

Smylers wrote:

 > Philip TAYLOR writes:

 >> [...] I believe that the specification should set out to address what is, and
 >> what is not, syntactically valid HTML; I do not think that it should
 >> attempt to define what is /semantically/ valid HTML,
 > I'm struggling to see how that'd be possible: how can we define, say,
 > the <h1> element without saying that its contents will be interpreted as
 > a heading?


 > That's saying that the contents of <h1> have the semantics of a heading
 > -- and therefore that to put something inside <h1> that isn't a heading
 > will cause an HTML-5-compliant interpretation of the document to ascribe
 > to it a different meaning from that intended by its author.  In other
 > words, the document with the meaning the author intended isn't valid
 > according to HTML 5.

Not agreed :-)  The specification must indicate the semantics of
each element, but if an author chooses to use (or erroneously uses)
the element with different semantics, then that cannot make the
document invalid.  I'm not even sure what adjective does describe
such a document, but I am convinced that "invalid" is inappropriate
here.  The classical example is as follows :

    1. Colorless green ideas sleep furiously.
    2. Furiously sleep ideas green colorless.

(1) is a sentence; it follows all the syntactic rules of the
     English language, yet makes no sense.  (2) is not
     a sentence; it violates some basic syntactic rules.

In the case we are discussing, the author would have written
a type-1 document; it would not be possible (using the grammar
of HTML) to deduce its meaning, but it would still be valid.
If, on the other hand, the author had written (say)

	<table><li> ... </head>

then that would be a type-2 document, and inherently invalid.

 > So if <table> is defined as marking up a data table then it simply isn't
 > valid to use <table> for anything else -- whether that be layout or any
 > other purpose.

Not agreed, for the same reason as above.  And much as I am on
the side of those who want tables to be used solely to present
tabular data, I am not convinced that there do not (or could not)
exists borderline cases in which the author believes that what he
or she is communicating is tabular data whilst others would
assert that the table is being (ab)used to communicate layout.

Received on Sunday, 1 March 2009 15:11:24 UTC

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