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Re: [MathML4] Deprecation/Removal of the mfenced element

From: Frédéric WANG <fred.wang@free.fr>
Date: Tue, 26 Jul 2016 09:02:23 +0200
To: Murray Sargent <murrays@exchange.microsoft.com>, "www-math@w3.org" <www-math@w3.org>
Message-ID: <636f3f8c-a072-c7ce-e88a-bbba943c677f@free.fr>
Le 25/07/2016 à 20:39, Murray Sargent a écrit :
> Hmm. I like <mfenced>. It's an element that says up front what it
> means. <mrow> is abstract and requires parsing before you know what it
> means. In Microsoft Office math, there is the "delimiters" element <d>
> that maps neatly into <mfenced>. The LineServices math handler formats
> such elements automatically expanding to fit their arguments. The
> result is math typography very much like TeX, but without the need for
> control words like \biggl.
> Our products can generate and input MathML using <mrow> instead of
> <mfenced>, but parsing similar to that used for the math linear format
> <http://www.unicode.org/notes/tn28/UTN28-PlainTextMath-v3.pdf> is used
> to convert to <d>.
As I see, this is an internal implementation details for the Microsoft
Word / LineServices that does not need to be exposed to the Web or
handled everywhere. You already have import/export features between
MathML to OfficeMath including between <mrow>/<mo> and <d> so I don't
see how it helps to have an <mfenced> element when you have to handle
the general case anyway.

MathML is centered around mrow and mo elements with a dictionary of
properties. Whether or not it is a good idea is a separate discussion,
but it's a core feature of MathML and is unlikely to be changed in the
future. That implies that you must implement these general cases anyway
and so mfenced or Office's n-ary elements are duplicate features that do
not bring anything new but pain for implementers.

I would really be curious to hear progress from the Edge developers
regarding the implementation of MathML. I'm dubious that the design of
mfenced (renderer text provided in attributes, parsing needed to expand
the element, duplicate of mrow+mo) make them happy.

Frédéric Wang

Received on Tuesday, 26 July 2016 07:03:00 UTC

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