/*

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;

}