Convert box commands

[Myriad-Dreamin]

No plan, but some direction:

• find a way of ignoring all box related commands, so that it just compiles in typst instead of really layout something.
• implement kern commands
• implement glue commands
• implement paragraph commands

Materials and ideas

• See ifdim
• See ifhbox
• See ifvbox
• See ifvoid
• See Box family in TUG.
• See Kern family in TUG.
• See Glue family in TUG.
• See Paragraph family in TUG.

Initial Idea is following.

• The boxes are allocated by converter.
• We may have infinite virtual box registers, since holding limit of 256 is just less meaningful but depends on implementation.
• We won't calculate any size of boxes, but converting them with typst scripting.
  That means, any failed conversions will just make MiTeX ignore layout request from TeX Code.
• For code converting layout, measure for box and box conditions:

  #locate(loc => layout(size => {
    // converted code here
  }))

Examples

Example 1 (paragraph):

\everypar{\setbox\parbox=
\vbox\bgroup\everypar{}%
\def\par{\endgraf\HandleLines
\egroup\box\parbox}}
\def\HandleLines{ ... \lastbox ... }

Example 2 (box):

\newbox\linebox \newbox\snapbox
\def\eatlines{
\setbox\linebox\lastbox % check the last line
\ifvoid\linebox
\else % if it's not empty
\unskip\unpenalty % take whatever is
{\eatlines} % above it;
% collapse the line
\setbox\snapbox\hbox{\unhcopy\linebox}
% depending on the difference
\ifdim\wd\snapbox<.98\wd\linebox
\box\snapbox % take the one or the other,
\else \box\linebox \fi
\fi}