/*
finds patterns with a single changing token occurring at least twice

inputs e.g. (with map splitAtSpaceTok(tlft(...))):
  kgopkgorkgorkogrkkkbla makes sense
  heldfdfdkfodkfodfkodlo makes sense
  but 12345! makes no sense
  but b1lubb makes no sense
  
will find:
  * makes sense [2]
  but * makes no sense [2]
*/

static MultiSet<S> findOneArgumentPatterns(LLS toks) {
  MultiSet<S> patterns = ciMultiSet();
  MultiMap<Int, LS> byLength = indexListsByLength(lambdaMap simpleSpacesAndTrim(toks));

  for (LLS toks2 : byLength.values()) {
    for (int i = 1; i < l(first(toks2))-1; i += 2) {
      int _i = i;
      MultiSet<S> set = mapToCIMultiSet(toks2, tok -> join(cloneListReplacingElementAtIndex(tok, _i, "*")));
      patterns.addAll(multiSetWithoutSingles(set));
    }
  }
  ret patterns;
}