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Removal/Deprecation of <mfenced> #2
Description
This proposal is to remove the <mfenced> element or at least deprecate it.
From the Math WG: https://lists.w3.org/Archives/Public/www-math/2016Jul/0004.html
From the original "MathML in HTML5" appendix: "The element is just a “convenient form in which to express common constructs involving fences” but is strictly equivalent to an expanded form with and elements and has many exceptions to handle. It is thus not actually necessary and just requires more code for implementers and may lead to rendering inconsistencies with the expanded form. It requires web rendering engines to create many “anonymous” rendering frames (or similar) and keep them up-to-date which may lead to rendering, performance or security issues. Because the text of fences and separators is included in attributes and not in MathML elements then by default it may not be possible to search, select, copy it. It may also not be exposed to assitive technologies without further effort. In this document support for mfenced is not required. Authors are encouraged to use the expanded form and we recommend that the element is dropped from future version of the MathML specification. "
Activity
fred-wang commentedon Feb 22, 2019
mfenced is currently not defined in MathML Core, so this is just for mathml4
dani31415 commentedon Feb 25, 2019
There is a precedent of content in an attribute that is selectable and exposed to the AT: the
valueattribute of theinputHTML tag.physikerwelt commentedon Feb 25, 2019
discussed in the telco on 2019-02-25:
fred-wang commentedon Mar 14, 2019
Polyfill has been moved to:
https://mathml-refresh.github.io/mathml-polyfills/mfenced/
https://github.com/mathml-refresh/mathml-polyfills/tree/master/mfenced
NSoiffer commentedon Apr 29, 2019
Based on the stats we have, mfenced is not used by converters. NAG uses it extensively, but the MathML spec defines its equivalence and so it doesn't add functionality. Given it's use, it would be wrong to deprecate from the full spec, but given it's equivalence, I don't see a need to keep it in core.
fred-wang commentedon May 16, 2019
Resolution:
Notes are not published yet but we agree to remove from core and keep in full?
Specification:
MathML Full probably needs update.
Implementation:
Need to remove from WebKit and Firefox.
No plan to implement it in Chromium.
Polyfill:
We have polyfills with manual tests at https://github.com/mathml-refresh/mathml-polyfills/tree/master/mfenced
As @bkardell pointed out we probably need to decide how we want our polyfill to look like to remain compatible with the rest of the web platform. Also we might other things like nodejs converters that can be embedded in MathML generators' pipeline. Anyway, probably a separate discussion.
I'm keeping "need polyfill" for the record.
Tests:
fred-wang commentedon May 16, 2019
(I added need resolution, until the notes are published and someone link them from here)
fred-wang commentedon Jun 3, 2019
Consensus: remove from core and keep in full
9 remaining items
Add tests for MathML features that we might remove from Core / unship…
Add tests for MathML features that we might remove from Core / unship…
fred-wang commentedon Oct 1, 2019
Test added so closing.
Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…
Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…
Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…
Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…
Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…
Make the SVG mfenced element deprecated
Refactor delimiter/bracket handling, account for recent deprecation o…
Yaffle commentedon May 11, 2021
Hello!
By the way, the same is true for the surd of
<msqrt>and<mroot>today.Bug 1585419 [wpt PR 19450] - Add tests for MathML features that we mi…