I have a user interface problem that I hope isn't only solved by adding yet another option for authors to understand.
Student types a mathematical expression. We allow implicit multiplication, so `xy` is interpreted as `x*y`.
What to do about `pi`? Is it `p*i` or `π`?
I guess most of the time, you'd expect it to be interpreted as π. But you might be doing something with complex numbers, and `p*i` is really what you meant.
I suppose rendering π would at least give you a hint to add the * symbol
@christianp If you render a preview on the fly, I would expect it to be clear. Especially if the student can see the `x*y` syntax somewhere (help text etc.). I would consider `p*i` about as logical interpretation as `s*i*n`.
@petrilaarne what about the letter ξ, transliterated as 'xi'? I reckon `x*i` is the most common interpretation of that.
The system already renders a preview of the interpreted expression on the fly, but students either ignore it or misinterpret it - if they're not expecting a multiplication symbol, they don't notice it's missing.
@christianp That’s an excellent counterexample. I agree that `x*i` could reasonably come up. A few years ago, I wouldn’t even have associated the word ”xi” with the letter ξ (the Finnish transliteration being ”ksii”).