{
    Let read text.
        Let n. (STRING.length text)
        In
        Begin (reading 0 0)
            Define reading i num.
                Cond
                | (i = n) `just.num
                | True
                    Let c. (STRING.fetch text i)
                    In
                    If And (c >= '0') (c <= '9')
                        Goto (reading (i + 1) (10 * num + c + -'0'))
                        `nothing
                ;

    Let show. Prim show_integer

    Let compare a b.
        Cond
        | (a < b) `less
        | (a > b) `greater
        | True `equal
        ;
}

Where

Let STRING. Package "string"