static S tok_groupAroundWord(S s, S word) {
  L<S> tok = defaultTok(s);
  int i = indexOf(tok, word);
  if (i < 0) ret s;
  ret curlyBraceIfMoreThanOneToken(joinSubList(tok, 1, i-1))
    + joinSubList(tok, i-1, i+1)
    + curlyBraceIfMoreThanOneToken(joinSubList(tok, i+1));
}