sS tok_groupFirstNTokens(S s, int n) {
  ret tok_groupFirstNTokens(javaTokWithAllBrackets(s), n);
}

sS tok_groupFirstNTokens(LS tok, int n) {
  ret first(tok) + curly(joinSubList(tok, 1, n*2)) + joinSubList(tok, n*2);
}