Do we **really** want bare symbol 'b' to be TeX-typeset in Roman?

[gwhitney]

Right now, pretty counterintuitively, math.parse('a').toTex() produces ' a' whereas math.parse('b').toTex() produces '\\mathrm{b}', on the theory that a bare symbol b is by default a valueless quantity of bits. I think that's the wrong or at least unexpected/undesirable result for 99% of use cases, especially as "b" for bits is a really rarely used unit symbol. It's much more likely that a bare b in an expression is just a plain ol' symbolic variable like a, and should be typeset in math italic. The current behavior is particularly egregious in a formula like log(b), where a Unit value isn't even allowed as an argument to log.

How can we adapt/configure/extend/improve .toTex() to get this correct from the client's perspective for the 99% of cases, while still allowing some way to get math.parse('5m').toTex() to put the m in Roman when the actual meaning really is 5 meters? Again, 'm' is such a common variable name to use in mathematical expressions that even though it's also a common unit, I bet at least half the cases of using this in a formula that's being converted to TeX want the italic 'm' for a variable, not the Roman 'm' for a unit, especially as toTex() seems much more likely to be used in a math setting than an engineering/unit-based setting. (The big overlap would be in a physics context, where both variables and units are pretty common, and where practitioners might be interested in converting a formula to TeX.)

Just brainstorming, the default behavior for toTex() could be to only look up multi-character symbols as far as whether they are units, and typeset all single-character symbols in math italic. Then we would have to add an option, something like asUnit: ['m', 'g'], for someone who wants single-character meters and grams symbols set as units.

Thoughts?