Tweaking lib/symbols for XML entities

[Thibaut Cuvelier]

Dear list,

In order to ensure a valid DocBook entity with math formulae, the MathML
generator must produce valid XML. Right now, it "only" produces valid HTML
(which is already quite an achievement!). The difference is in the
entities: in HTML, you can use many entities, like ∑. This is no more
the case in XML, where you have to define all entities (that is, besides
<, >, &, ", '). A solution for DocBook would be to
define the needed entities in the XML document, but that would require
generating all math formulas, remembering the needed entities, then output
the mapping at the *beginning* of the XML document.

There are mostly two places where these entities are hard-coded in LyX:
InsetMathDecoration, with only a few entities hard-coded in source code;
lib/symbols, a much harder thing to change.

Here is what I came up with:
https://gitlab.com/gadmm/lyx-unstable/-/merge_requests/3/diffs?commit_id=0c0fc7624caad400f22072442f9132291ee3036d#e90e8f11b4a89e64b3c66669958e7af650b2f526.
It adds a parameter to MathStream to enable outputting XML-valid entities.
Mappings for InsetMathDecoration are done by slightly adapting the data
structure. However, for the other entities, I hard-coded a mapping in
InsetMathSymbol (hundreds of entities…), because I could not get my head
around lib/symbols. (By the way, in this file, are the "x" mappings symbols
that are not yet allowed in output?)

Would the patch be acceptable as-is?
Otherwise, could a lib/symbols expert (I've heard that there might be one
roaming around) help me with this? As I understand it, it would be adding a
new column in this file to propose an XML entity after the HTML one.

I also attach two patches for MathStream: the second one is my current
tentative of implementing XML entities; the first one is about adding
XML-name-spaces support (and not really related to the question above, but
the second one relies on it to avoid conflicts when merging). Only the
second one has been reviewed by Guillaume.
Of course, if these patches look OK to you, I'd be happy to see them
merged! It's unlikely I'll need to change something there in the near
future.

Kind regards,
Thibaut Cuvelier
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lyx.org/pipermail/lyx-devel/attachments/20200510/107ba15a/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0005-MathML-stream-allows-for-name-spaces.patch
Type: application/octet-stream
Size: 40368 bytes
Desc: not available
URL: <http://lists.lyx.org/pipermail/lyx-devel/attachments/20200510/107ba15a/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0016-Convert-HTML-entities-to-XML-entities.patch
Type: application/octet-stream
Size: 44832 bytes
Desc: not available
URL: <http://lists.lyx.org/pipermail/lyx-devel/attachments/20200510/107ba15a/attachment-0003.obj>