Typing lambdabar gives a math error

[jolyonb]

Oh Asciimath, why do you taunt us so?

[jolyonb]

Here's a new one: deltaE+ gives a math error too.

[ChristopherChudzicki]

Without our preprocessEqn

similar to lambdabar:

• {:bar:} (we already prevent this from happening in preprocessEqn see Asciimath nowrap overscripts #170 )
• {:fbar:} error
• {:fdot:} error

Seems a group ending in any math-over symbol is bad.

similar to deltaE+:

• {:f:}+ no error
• {:ff:}+ error
• {:fff:}+ no error

Asciimath seems to parse these expressions just fine. It's mathjax that isn't rendering them. I should learn more about mathjax and edX's configuration in particular...

[jolyonb]

I think edX's MathJax version is somewhat out of date. They're planning to update it with the python3 push, so perhaps this isn't worth figuring out just at this moment.

[ChristopherChudzicki]

Re lambdabar, Asciimath wants barlambda for "lambda with a bar on top". I'm guessing you want physics lambdabar, though, in which case we should do it like hbar and use this unicode symbol: https://www.fileformat.info/info/unicode/char/019b/index.htm

I'm out till this afternoon.

[jolyonb]

Yeah, I do convert it to unicode. I'd just like to stop math processing errors from displaying!

[jolyonb]

So, edX appears to be using MathJax 2.7.5, which is the latest version. However, all of these issues appear to be fixed in the latest version of AsciiMath (http://asciimath.org/) and MathJax (https://www.mathjax.org/#demo), so there seems to be a bug in the edX configuration. I don't think this is something we should be worrying about; I've reported the bug to edX.

[ChristopherChudzicki]

OK. Still, do you want

// This is lambdabar, angular wavelength
      AM.newsymbol({
        input:"lambdabar",
        tag:"mo",
        output:"\u019b",
        tex:null,
        ttype:AM.TOKEN.CONST});

in our default updateMathJax()? This works fine in edX for me for generating

(Although {:deltaE:}+{:lambdabar:} still gives a mysterious error on edX, but not on MathJax preview site.)

[jolyonb]

Not in the default. I currently do

eqn = eqn.replace(/lambdabar/g, '\u019B');

to make it work, which works fine.

That last one you found is really annoying... changing lambdabar to hbar also has the error. I don't think there's much to be done though :-(