static S jreplace_first_dyn(S s, S in, O out) {
  ret jreplace_first_dyn(s, in, out, null);
}

static S jreplace_first_dyn(S s, S in, O out, O condition) {
  L<S> tok = javaTok(s);
  ret jreplace_first_dyn(tok, in, out, false, false, condition) ? join(tok) : s;
}

// leaves tok properly tokenized
// returns true iff anything was replaced
static boolean jreplace_first_dyn(L<S> tok, S in, O out) {
  ret jreplace_first_dyn(tok, in, out, false, true, null);
}

static boolean jreplace_first_dyn(L<S> tok, S in, O out, O condition) {
  ret jreplace_first_dyn(tok, in, out, false, true, condition);
}

static boolean jreplace_first_dyn(L<S> tok, S in, O out, boolean ignoreCase, boolean reTok, O condition) {
  L<S> tokin = javaTok(in);
  jfind_preprocess(tokin);

  boolean anyChange = false;
  int i = 1;
  if ((i = findCodeTokens(tok, i, ignoreCase, toStringArray(codeTokensOnly(tokin)), condition)) >= 0) {
    L<S> subList = tok.subList(i-1, i+l(tokin)-1); // N to N
    S expansion = cast callF(out, tok, i);
    int end = i+l(tokin)-2;
    clearAllTokens(tok, i, end); // C to C
    tok.set(i, expansion);
    if (reTok)
      reTok(tok, i, end);
    anyChange = true;
  }
  ret anyChange;
}

Began life as a copy of #1019424