// optionally convert expression to return statement
static S tok_addReturn(L<S> tok) {
  if (tok_shouldAddReturn(tok)) {
    tokPrepend(tok, 1, "return ");
    tokAppend(tok, l(tok)-2, ";");
  }
  ret join(tok);
}

static S tok_addReturn(S s) {
  ret tok_addReturn(javaTok(s));
}