vim9script

# Based on https://vim.fandom.com/wiki/Move_to_next/previous_line_with_same_indentation

export def Do(step: number, diff: number)
    var l = line(".")
    var cin = indent(l)
    var last = line("$")
    var lin: number
    while (l > 0 && l <= last)
        l += step
        if (strlen(getline(l)) == 0) | continue | endif
        lin = indent(l)
        if !(
            ((diff == 0) && (lin == cin)) ||
            ((diff == 1) && (lin > cin)) ||
            ((diff == -1) && (lin < cin))
        ) | continue | endif
        cursor(l, lin + 1)
        return
    endwhile
enddef