fun duplicate str = str ^ str ;

fun clip str = substring(str,0,size str -1);
fun middle str = substring(str, size str div 2,1);
fun dtrunk str = substring(str, 1 , size str - 2);
fun incFirst stri = str(chr (ord (String.sub(substring(stri,0,1),0)) +1)) ^ substring(stri, 1 , size stri - 1);
fun switch stri = substring(stri,size stri div 2, size stri - size stri div 2) ^ substring(stri, 0,size stri div 2) ;

val first = str o hd o explode;
val second = str o hd o tl o explode;
val third = str o hd o tl o tl o explode;
val fourth = str o hd o tl o tl o tl o explode;
val last = str o hd o rev o explode;

fun roll s = fourth s ^ first s ^ second s ^ third s;
fun exch s = second s ^ first s ^ third s ^ fourth s;

val what = roll o roll o roll o exch o roll;

val fb = roll o roll o roll;
val fc = roll o exch o roll o roll o roll;
val fd = roll o exch o roll o roll o exch o roll o roll;