## New $...$ bbCodes

Dave Keenan
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### New $...$ bbCodes

You can now include beautiful math expressions in your posts, using $$\LaTeX$$ thanks to this MathJax phpBB extension by Kailey Truscott. Thanks to @cmloegcmluin for suggesting this. And of course, thanks to Donald Knuth, Leslie Lamport and the MathJax team.

For example

$$x = {-b \pm \sqrt{b^2 - 4ac} \over 2a}$$

was generated by:

$x = {-b \pm \sqrt{b^2 - 4ac} \over 2a}$

It can also be written:

$x = { -b \pm \sqrt{b^2 - 4ac} \over 2a }$

Non-breaking spaces were used to achieve the indenting above.

There are many online sources of information about LaTeX. Here's one:
https://en.wikibooks.org/wiki/LaTeX/Mathematics#Symbols

And here's one of several online LaTeX editors:
http://www.hostmath.com/

Now all we need is a way to include Sagittal music scores in our posts.

cmloegcmluin
Posts: 1684
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Location: San Francisco, California, USA
Real Name: Douglas Blumeyer (he/him/his)
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### Re: New $...$ bbCodes

The pressure is on, now! (to write some beautiful equations) Good thing I got a little practice with LaTeX earlier this year on the Xen wiki (linking not for self-promotion, of course... but for the benefits of others, including future versions of myself, who may want to leverage some techniques I used there).

Re: Sagittal scores, I think the summary of where we're at on that front is this: Daniel said we shouldn't expect to get Bravura working in the browser without the assistance of a library such as Vexflow, and I've been pestering them for months to get Sagittal support included in their library but with no response. With enough time I could figure out how to do it myself, but perhaps I can wait that battle out.

Dave Keenan
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Joined: Tue Sep 01, 2015 2:59 pm
Location: Brisbane, Queensland, Australia
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### Re: New $...$ bbCodes

Woah. That Metallic MOS article has grown a lot since I last saw it.

Another angle on getting scores into the forum was to get Bravura Text accepted as a Google Font, which required it to have the full ASCII set plus a few other common characters, and therefore required it to use Unicode space characters instead of "=" and "-" for staff spacing.

Another was to get a .woff version of Bravura Text that wasn't broken.

Dave Keenan
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Joined: Tue Sep 01, 2015 2:59 pm
Location: Brisbane, Queensland, Australia
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### Re: New $...$ bbCodes

It looks like the MathJax extension has broken something. There's some weirdness happening with backquote characters  also called graves. You can see it here with some text that was surrounded by backquotes.

viewtopic.php?p=1327#p1327

My first thought was that ... might be equivalent to $...$. But when I surround the following with backquotes

x = {-b \pm \sqrt{b^2 - 4ac} \over 2a}

I get

x = {-b \pm \sqrt{b^2 - 4ac} \over 2a}

It fails to interpret the \over macro.

In any case, this is very annoying. I saw nothing in the MathJax extension documentation about commandeering backquotes.

Fortunately this doesn't break the Sagittal smilies that use backquotes

cmloegcmluin
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Joined: Tue Feb 11, 2020 3:10 pm
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Real Name: Douglas Blumeyer (he/him/his)
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### Re: New $...$ bbCodes

AsciiMath, I think that must be: http://docs.mathjax.org/en/latest/basic ... math-input

Perhaps this is okay, though. I'm happy to fix the backquotes on that post. For multiple lines of code, we have the [code] bbCode. And for inline tokens of code, it's not like the backquote formats it differently here (as would be the case in code-specific markdown settings e.g. GitHub), so normal quotes should be just fine. Or if you want you can always do something like this: monospace (that's [font=monospace][hilite=white]monospace[/hilite][/font]).

Dave Keenan
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Joined: Tue Sep 01, 2015 2:59 pm
Location: Brisbane, Queensland, Australia
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### Re: New $...$ bbCodes

Ah. Thanks for explaining that. AsciiMath? Who asked for that? (Rhetorical)

I've now learned that not only does MathJax eat backquotes outside of $...$, it also eats the sequences $$...$$, $...$ and $$...$$, all of which I've been forced to escape* so you can see them here. The last two are equivalent and produce a centered "display" expression from LaTeX source, instead of an inline expression. Try them.

In fact the $...$ bbCode simply translates to <span>$$...$$</span> before the whole page is fed through MathJax. Fortunately it doesn't break the :|\): = smiley either.

Yes. Please escape or replace the backquotes in that post, and any others you're aware of.

* Other readers may not be aware that a hack for escaping bbCode tags and smiley/emoji codes (and now AsciiMath and LaTeX tags) is to surround their first character with [size=100]...[/size].

I've learned that it should be possible to eliminate all these nasties by creating our own local MathJax configuration file, and pointing to it from sagittal/forum/ext/kinerity/mathjax/styles/prosilver/template/event/overall_footer_after.html which contains a single line:

Code: Select all

<script type="text/javascript" async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/MathJax.js?config=TeX-MML-AM_CHTML"></script>`
This is explained here:
https://docs.mathjax.org/en/v2.7-latest ... nfig-files
and here:
https://docs.mathjax.org/en/v2.7-latest ... igurations
but it seems like a lot of work.

I guess I can live with the backquotes thing, and the two-character LaTeX tags shouldn't cause a problem.

cmloegcmluin
Posts: 1684
Joined: Tue Feb 11, 2020 3:10 pm
Location: San Francisco, California, USA
Real Name: Douglas Blumeyer (he/him/his)
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### Re: New $...$ bbCodes

Cool beans!

$$F_n = { \phi^n - (-\phi)^{-n} \over \sqrt5}$$

Shouldn't be that hard to modify the extension by those instructions actually. Won't be my first priority though. I've filed it though.