Ostap Bender: The Great Combinator (of Stylus): http://codepen.io/thybzi/pen/PZMPob

ostap.styl

// Get both inverse and forward combinated subject and current selector
// Example: .parent > .curr + .subj, .parent > .subj + .curr
// If subj is omitted, get current selector combinated with itself
// Example: .parent > .curr + .curr
// Limitation: Fails if parent selector level contains more that one combinator
// Limitation: Nesting calls cause exception
combinate(comb, subj='^[-1..-1]')
  parts = ('&' + pad-combinator(comb) + subj)
  if subj != '^[-1..-1]'
    push(parts, combinate-inv(comb, subj))
  return join(', ', parts)

// Get inverse combinated subject and current selector
// Example: .parent > .subj + .curr
// Limitation: Fails if parent selector level contains more that one combinator
// Limitation: Nesting calls cause exception
combinate-inv(comb, subj='^[-1..-1]')
  pcomb = get-combinator('&')
  comb = pad-combinator(comb)
  return '../' + pcomb + subj + comb + '^[-1..-1]'

// Get last combinator applied
get-combinator(sel)
  scurr = selectors(sel)[-1]
  combs = ('~' '>' '+')
  notcombs = '\s*[^' + join('', combs) + ']+\s*'
  for comb in combs
    esc = (comb == '+') ? '\\' : ''
    if match(esc + comb + notcombs + '$', scurr)
      return pad-combinator(comb)
  return ' '
  
// Surround combinator with spaces, if necessary
pad-combinator(comb)
  if comb != ' '
    comb = ' ' + comb + ' '
  return comb
  

// Let the fun begin!
.wrapper + .parent

  & > figure
    /*!* Test #0 (inverse combinator pre-check): SUCCESS */   
    {combinate-inv('+', '*')}
      color: #000
  
  & > figure
    /*!* Test #1 (single parent combinator, default subj): SUCCESS */ 
    {combinate('+')}
      color: #111
      
    /*!* Test #2 (single parent combinator): SUCCESS */ 
    {combinate('~', '*')}
      color: #222
  
  & figure
    /*!* Test #3 (space parent combinator): SUCCESS */
    {combinate('~', '*')}
      color: #333
      
  figure
    /*!* Test #4 (implicit space parent combinator): SUCCESS */
    {combinate('~', '*')}
      color: #444
      
  & > figure + p
    /*!* Test #5.1 (two parent combinators): FAIL TO GET PARENT COMBINATOR */
    {combinate('~', '*')}
      color: #515151
      
    /*!* Test #5.2 (two parent combinators, default subj): TOTAL EPIC FAIL */
    {combinate('~')}
      color: #525252

  & > figure
    /*!* Test #6 (nested): FAIL WITH EXCEPTION */
    // {combinate-inv('+', 'p')}
      // color: #616161
      
      // {combinate-inv('~', 'h1')}
        // color: #626262