Question

I want to to perform computations with large integers in SML, through functions like pow in this link:

http://www.standardml.org/Basis/int-inf.html#IntInf:STR:SPEC

But how do I get to use this “library”?

---

UPDATE:

Thanks for the answer. I got it. I also had to change the limit for printing with

Control.Print.intinfDepth := 10000;

I made my own pow function for IntInfs (and it works) like this:

fun power 0 = IntInf.toLarge 1
  | power n = IntInf.toLarge 2 * power(n-1);

Answer 1

It depends on which implementation you use, but generally you need to convert your Int’s to LageInt/InfInf types with the Int.toLarge:

(* will be types as an IntInf *)
val aa = 10983298432984329843298432984329843298432987987987432987987987432987
val a = IntInf.pow(aa,10);

(* explicit type as if some other constraint had enforced this*)
val b = 10 : int
val c = Int.toLarge b;

val d = IntInf.pow(c, b);

The variable aa may not be parsed in your interpreter. It depends on what you use. I have tested it in poly and mlton.

where the above gets the types (given by mlton with -show-basis flag):

val a: intInf
val aa: intInf
val b: int32
val c: intInf
val d: intInf