W3C home > Mailing lists > Public > www-math@w3.org > December 2014

Re: Ideas for future improvements

From: William F Hammond <hammond@csc.albany.edu>
Date: Fri, 05 Dec 2014 03:05:26 -0500
To: Frédéric WANG <fred.wang@free.fr>
Cc: <www-math@w3.org>
Message-ID: <i7h9xaa5dl.fsf@hilbert.math.albany.edu>
Frédéric WANG <fred.wang@free.fr> writes:

> - The structure is quite different because the operators in <mfenced>
> are in attribute values rather than in elements. As a consequence,
> native implementations need to create anonymous frames to represent
> these operators.

Not if the fences wind up being constructed with CSS as enhanced border
decorations (somewhat beyond what is presently available in CSS) with
precise effortless stretching as a bonus.  Having the fence specs
in <mo>'s would be awkward for that.

Moreover, the fence operators are not semantically the same
as other operators, and there is no definitive way to tell
whether operators that are fence-like first and last
children in <mrow> are really there as fences.  For example,
in [f(x)]_{x=a}^{x=b} (which resolves as math to f(b)-f(a))
the brackets are non-fence operators.  Of course,
presentation mathml is semantically poor from the outset,
but this doesn't mean that whatever semantics are there
should be trashed.

> - Deprecating will not break conforming implementations (they implement
> the two versions, as currently required by the spec) but only poor
> implementations like the one that used to be in Opera. As said by
> William, the only risk is breaking old documents.

Don't forget that there are many implementations other than browser
rendering, both for generating mathml and for consuming it.

If people believe that MathML documents are not durable at least for
the extent of their lifetimes, they will run from MathML.

Don't we remember the breakage in Firefox when <mlabeledtr>
was pulled from Firefox?  It had consequences.  Yes, that
element was of limited use, but it had some use, some were
using it, and they were annoyed.

> What I'm proposing is that browsers display a deprecation
> warning and encourage people to move to the equivalent
> version, to prepare future removal in a (very) long term.

It would also break the paradigm of XML.  A document spec-ed as
XHTML 1 + MathML 2 should be durable forever.

BTW, I believe there has been this debate about <mfenced>
virtually from the beginning of mathml.

                                    -- Bill
Received on Friday, 5 December 2014 08:05:52 UTC

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