Everymath

[brucemiller]

Use \everymath, \everydisplay correctly. The latter is used (alone) for displayed math, the former for inline math. Add some tests.

[dginev]

Well, it is certainly more correct than before. But there are likely further hidden inaccuracies for more custom math environments.

As an example test of a subtlety, the left-arrow here surprised me in the PDF (and neither arrow shows up via this PR):

{
 \everymath={\leftarrow}
 \everydisplay={\rightarrow}
 \begin{equation}
  a+b
 \end{equation}
}

[dginev]

Good to merge, just flagging that there are more icebergs out there...

[brucemiller]

Ah, yes. Painfully obvious, now that you point it out. Thanks!
So, here's a slightly scarier, but more complete version.

[dginev]

Good to merge, nice upgrade.

[dginev]

Very nice simplification. The cherry on the cake would be to switch the few cases of

beforeDigest => sub { $_[0]->beginMode('display_math'); }

to the abbreviated form of

mode => 'display_math'

[brucemiller]

Ha! I fell into that trap! (& wasted time). It's subtly different. That short form simply switches the mode (typically within an environment which establishes a grouping), whereas the commands in question like \lx@begin@displaymath come in pairs which will do beginMode and endMode.

[dginev]

Ah! mode also ends the mode at the end, indeed that slipped my mind. Apologies.