/* complicated version - TODO */
// for (S key, S value : map)
/*static void doubleFor(L<S> tok) {
  int i;
  while ((i = jfind(tok, "for (<id> <id>, <id> <id> :")) >= 0) {
    int iComma = indexOf(tok, ",", i);
    S valType = tok.get(iComma+2);
    S valName = tok.get(iComma+4);
    int expStart = indexOf(tok, ":", i)+2;
    int expEnd = findEndOfBracketPart(expStart-2);
    assertEquals(")", tok.get(expEnd));
    assertEquals("{", tok.get(expEnd+2));
    replaceTokens(tok, iComma, expStart, ": keys(");
    tok.set(expEnd, "))");
    tok.set(expEnd+2, "{ " + valType + " " + valName + " = " + 
    S type = tok.get(i+2), id = tok.get(i+4);
      int j = scanOverExpression(tok, bracketMap, i+8, "|");
      S exp = join(tok.subList(i+8, j));
      j += 2;
      int k = scanOverExpression(tok, bracketMap, j, "]");
      S where = join(tok.subList(j, k));
      ++k;
      
      S code = "filter(" + exp + ", func(" + type + " " + id + ") { " + where + " })";
      replaceTokens(tok, i, k, code);
      reTok(tok, i, k);
    }
}*/