current situation

types:

• rendered in display mode: Latex_Environment & Displayed_Math
• rendered in inline mode: Latex_Fragment Inline/Display

syntax:

1. $content$, TeX delimiters for inline math -> Latex_Fragment Inline

   • cannot start/end with a space (defined behavior) Confusing behavior of LaTeX with trailing space logseq#4170
   • cannot be multi-line

2. $$content$$, TeX delimiters for displayed math

   • $$ appears at the start of a line -> Displayed_Math
     • can be multi-line
     • good cases
       • Used like codeblocks
       • Only $$content$$ in one line, no other content later
     • bad case: $$content$$ content Inline math gets displayed in a block when placed at the start of a line logseq#4066
   • otherwise -> Latex_Fragment Display
     • cannot be multi-line

3. \( content \) , LaTeX delimiters for inline math -> Latex_Fragment Inline

   • cannot be multi-line

4. \[ content \], LaTeX delimiters for displayed math -> Latex_Fragment Display

   • cannot be multi-line

5. \begin{env} content \end{env}, LaTeX environment-> Latex_Environment

My improvement ideas

• Allow multi-line for all Latex_Fragment. And allow $ content $

  I'm actually interested why they don't support multi-line now. Is there a design consideration?

  By the way, I don't understand why \(\) and \[\] don't support multi-line text, since they use end_string.
  (Instead, $ use take_while (fun x -> x <> '$' && x <> '\r' && x <> '\n'), which banned \n explicitly

• Remove Displayed_Math since it's confusing. And in Logseq, let Latex_Fragment Display rendered in display mode.

  For $$, If there's nothing before the starting $$ and nothing after the ending $$, parse it into Latex_Fragment Display. Otherwise Latex_Fragment Inline.

i.e.,

$$a
b$$

and

$$a$$

are displayed math. But

$$a
$$b

and

$$a$$b

is equivalent to $a$b

For reference (and also an aternative), Typora's behavior:

• $$ and $ can both be multi-line
• displayed math only when used like codeblocks, i.e.,

$$
a
$$

The first two examples above are both inline math.