Add rules to map from non-combining to combining accents

[fred-wang]

Original thread: https://lists.w3.org/Archives/Public/www-math/2018Mar/0001.html
Also from the MathML in HTML5 note tracker: https://gitlab.com/mathml/MathMLinHTML5/issues/33

I think such a rule should be in MathML Core.

[fred-wang]

David did https://mathml-refresh.github.io/mathml-core/#comb-equiv

[fred-wang]

However, I think the MathML Core text still has to be adjusted and refer to that table.

[davidcarlisle]

@fred-wang yes in fact I had never really extracted or looked at that data from unicode.xml since adding it during the email discussion, so I just added more or less raw tables into that appendix. To be decided if it needs an appendix or should just be a table in the main body, also I am not sure we need to display the "reverse direction" table. But at least the raw data is now there.

[fred-wang]

@davidcarlisle where is the latest version of unicode.xml ; http://www.w3.org/2003/entities/2007xml/unicode.xml seems not up-to-date?

[fred-wang]

https://github.com/mathml-refresh/xml-entities I guess

[davidcarlisle]

https://github.com/mathml-refresh/xml-entities I guess

which is the same as the one in the W3C github at https://github.com/w3c/xml-entities/ The one in W3C TR space is older

…

On Tue, 18 Jun 2019 at 09:36, Frédéric Wang ***@***.***> wrote: https://github.com/mathml-refresh/xml-entities I guess — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <https://github.com/mathml-refresh/mathml/issues/11?email_source=notifications&email_token=AAJVYATPWMPFWYSW7JADZWLP3CNAXA5CNFSM4GYYLC72YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODX5UFVY#issuecomment-503005911>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAJVYARFMRAE42ARP5S2G3DP3CNAXANCNFSM4GYYLC7Q> .

[fred-wang]

I think it would be good to have one "official" version to use/edit.

[davidcarlisle]

Sure but it is same as mathml-full spec (and potentially core as well) we are using the mathml-refresh github as that gives full admin control and we can generate new repositories and give write access as required, but if we move to a REC track process (I think) we will need to move to a W3C organisation github, however I am assuming a workflow that doesn't edit on on the w3c repository we just periodically merge in changes from mathml-refresh

So historically all edits to unicode.xml for several years have been at https://github.com/w3c/xml-entities/ but I think the current policy should be that edits happen in mathml-refresh (https://github.com/mathml-refresh/xml-entities ) and are then merged across to https://github.com/w3c/xml-entities/

[fred-wang]

For MathML Core, I think we only want non-combining => combining mapping.
And actually an ordered list of combining characters so that browsers can try them in a determined order.
I'll try to update the spec for that.

[fred-wang]

I had set https://mathml-refresh.github.io/mathml-core/#combining-character-equivalences to "non-normative" ; we should defer the details for accents to a next version of core.

[Omikhleia]

Greetings,

My apologies is this is not the right issue, but the topic seems closely related:
Is non-normative appendix B.3 in MathML Core supposed to be complete?

Checking the Editor's Draft 26 November 2024 (it is unchanged to that respect vs. the Working Draft 27 November 2023 unless mistaken), it would seem to me that the following equivalences at least are missing.

U+030A > U+02DA (combining ring above > ring above)
U+0331 > U+00AF (combining macron (below) > macron)
U+0333 > U+2017 (combining double low line (below) > double low line)
U+034D > U+2194 (combining left-right arrow (below) > left right arrow)
U+20D0 > U+21BC (combining left harpoon (above) > leftwards harpoon with barb up)
U+20D1 > U+21C0 (combining right harpoon (above) > rightwards harpoon with barb up)
U+20D6 > U+2190 (combining left arrow (above) > left arrow [or U+27F5 long leftwards arrow?])
U+20E1 > U+2194 (combining left right arrow above > left right arrow)
U+20EC > U+21C1 (combining rightwards harpoon with barb downwards > rightwards harpoon with barb downwards)
U+20ED > U+21BD (combining leftwards harpoon with bard downwards > leftwards harpoon with barb downwards)
U+20EE > U+2190 (combining left arrow (below) > left arrow [or U+27F5 long leftwards arrow?])

And perhaps (debatable) [edited]
U+20DB > U+2026 or U+22EF (combining triple underdot (above) > horizontal ellipsis, or midline hoizontal ellipsis)
U+20E8 > U+2026 or U+22EF (combining triple underdot (below) > horizontal ellipsis, or midline horizontal ellipsis)

But maybe I am misunderstanding the scope of this appendix?

EDIT: Or of course the inverse table for combining > non-combining (I'm still at loss understanding how to render accents in our MathML engine)