static void tok_replaceWith(L<S> tok) {
  int i;
  while ((i = jfind(tok, "replace <id> with")) >= 0) {
    S token = tok.get(i+2);
    int repStart = i+6;
    int repEnd = smartIndexOf(tok, repStart, ".");
    S replacement = joinSubList(tok, repStart, repEnd-1);
    clearTokens(tok, i, repEnd+1);
    print("Replacing " + token + " with " + replacement + ".");
    int end = findEndOfBlock(repEnd)-1;
    for (int j = repEnd+2; j < end; j += 2)
      if (eq(tok.get(j), token)) tok.set(j, replacement);
    reTok(tok, i, end);
  }
}