How to implement tab stops?

Questions
4

Thanks for your answer. I used your nice idea with metadata and implemented a tabed environment myself. So far its working quite well.

#let t = metadata("tab")

#let tabed(c, tab_width: 1.55cm) = context {
  let rows = c.children.split(linebreak())
  for (j, row) in rows.enumerate() {
    let advance = 0.0pt
    let num_tabs = 0
    let cont = []
    for child in row + (t,) { // add extra tab stop for loop logic
      if child == t {
        if (num_tabs == 0)  {
          advance += measure(cont).width
          cont // emit content
          cont = []
        }
        num_tabs += 1
      } else {
        if (num_tabs > 0) {
          let column = calc.trunc( advance / tab_width )   // column where the first tab is located
          let advance_by = tab_width * (column + num_tabs) - advance
          h(advance_by) // emit space
          advance += advance_by
        }
        cont += child
        num_tabs = 0
      }
    }
    if (j < rows.len() - 1) {linebreak()} // emit line break
  }
}