static LS javaTok_simpleSpacesAndTrim(S s) {
  ret javaTok_simpleSpacesAndTrim(javaTok(s));
}
  
static LS javaTok_simpleSpacesAndTrim(LS tok) {
  int n = l(tok);
  for (int i = 0; i < n; i += 2) {
    int nIdx = i;
    S space = tok.get(nIdx);
    S prev = get(tok, nIdx-1), next = get(tok, nIdx+1);
    
    if (empty(space)) // no space anyway? keep that
      space = "";
    else if (prev == null || next == null) // end of string - no spaces either
      space = "";
    else if (isBracket(prev) && isBracket(next))
      space = "";
      
    tok.set(i, space);
  }
  ret tok;
}