Create a new matching-tag-pair textobject?

Question

Vim provides a builtin textobject t that captures a matched pair of HTML tags — so e.g. if you start with this <i>that█ <b>those</b></i>, then typing dat in normal mode leaves you with this█. Very cool.

How might I create similar textobjects for other markup languages with this sort of begin/end syntax? For instance, if I wanted one that captures the a matched pair of Liquid tags, or a matched LaTeX \begin{foo} and \end{foo} tag pair, where might I start?

I'm willing to do some digging and to write my own code, but seeing an example where someone has accomplished something similar would be very helpful.

Answer 1

I know a reference to a plugin is not an ideal answer, but this is a tricky thing to accomplish generally and I maintain a plugin which seems to do exactly what you ask for so I'll mention it.

The plugin match-up supports text objects a% and i% corresponding to pairs which were originally defined by matchit's % (matchit is a built-in plugin in vim which supports only visual-mode a% and is a bit inconsistent).

You can customize it with b:match_words like so:

au FileType file let b:match_words = '\begin{\(\w\+\)}:\end{\1},(:)'

It supports LaTeX out of the box (more extensively than VimTeX), and you probably won't need to define your own pairs for many languages.

Answer 2

one of the cool plugins to trait tag is vim surround
let's try out visual mode the that█ then:S<i>.

this <i> that█   <i>

to remove this tag use d s t

OR do manually

• if you want to delete a tag
  vatatd
  • vat select select by tag
  • at extend select to another outside tag
  • ... you can extend tag also if you want
  • d delete selected text
• if you want to remove the tag only
  yitvatatp
  • yit yank text
  • vat select select by tag
  • at extend select to another outside tag
  • ... you can extend tag also if you want
  • p past yanked text