@PauloCereda :) You're probably the tenth person to send me that, at least :þ Usually with the message: "Heard this for the first time. Immediately thought of you." XD
@daleif Maybe a small misprint (or I miss something): In ftp.acc.umu.se/mirror/CTAN/macros/latex/contrib/mathtools/…, page 28, where it is described why the \mathopen is important, the example should perhaps be \braket{A}{-B}{C} instead of \braket{A}{-B}, since \braket takes three arguments.
@PauloCereda oh gosh! That's a tough question! There are so many. Of his own probably Everything You Know Is Wrong and of the covers White and Nerdy :þ
@Skillmon The last few updates have been quite annoying - for me, the recognition of the system theme is now broken. FF goes from light mode into dark mode, but not the other way round, so each morning it is stuck there :(
(I was actually wondering why there were \mathopen in the example. Why just open? Could it have been some other class, just to avoid the ord-bin-ord situation? It did not seem logical to me.)
Is there an easy test for whether a control sequence token corresponds to a font slot (not sure I'm saying this the right way) or something else? That is, I am looking for an easy test that can detect tokens like \$, \#, \$, etc. I am not looking to detect something like \mymacro, where \mymacro has, for example, been def'fed to an "A".
@DavidCarlisle I see that works for \# and \%, but not for \$ nor \_. But if I can even reduce the special case exceptions to test for, that is a help. Thanks!