[Texmacs-dev] Native Commutative Diagrams

[Owen Lynch]

Hello,

I'm a semi-lapsed TeXmacs user. I love TeXmacs, but a majority of my 
mathematical work uses commutative diagrams, and the friction between TeXmacs 
and xypic is one of the big reasons why I head to LaTeX a lot.

The way that tikzcd/xypic does commutative diagrams is very natural; the items 
are put into a grid, and then arrows are drawn between them. It seems to me 
that this could be a great match for TeXmacs; all that would have to be done is 
add support for arrows to a subclass of the existing "table" layout. I know 
that commutative diagrams could be done with the figure drawing interface, 
however it's just not convenient enough to produce commutative diagrams in 
volume.

Essentially my idea is to subclass table and add a list of arrows with source 
and target. Then during layout, after the layout of each of the table cells has 
been calculated, each arrow would go from the boundary of its source cell to 
the boundary of its target cell.

As a newbie to the TeXmacs source, I would like to ask for some guidance about 
how to go about implementing this, however. Should it be done in C++, or could 
it be done in pure scheme? Are there "developer docs" somewhere that I should 
look at? Are there previous attempts along these lines, or similar pieces of 
code which I could look to for calculating the arrow source/targets? What is 
the minimal implementation of this that would get a commutative diagram on the 
screen, so that I can work off of that for developing the UI? Ideally, the UI 
would end up looking something like: https://tikzcd.yichuanshen.de/.

-Owen