Lisp / Vim: highlight surrounding expression

lisp.vim

augroup vlime_hilight_curr_expr
    autocmd!

    if empty(prop_type_get('lisp_curr_expr'))
        call prop_type_add('lisp_curr_expr', {'highlight': 'LispCurrExpr'})
    endif
    hi link LispCurrExpr MatchParen

    function! s:HilightCurrExpr() abort
        call prop_remove({'type': 'lisp_curr_expr', 'all': v:true})

        let expr = vlime#ui#CurExpr(1)
        if expr[0] == '' || expr[1][0] == 0
            return
        endif

        let [line1, col1] = expr[1]
        let [line2, col2] = expr[2]
        let l:options = {
                    \   'type': 'lisp_curr_expr',
                    \   'end_lnum': line2,
                    \   'end_col': col2,
                    \ }
        call prop_add(line1, col1, l:options)
    endfunction

    autocmd CursorMoved,CursorMovedI <buffer> call s:HilightCurrExpr()
augroup end