bin2peano(Cons(B0,Nil)) = Z
bin2peano(Cons(B1,Nil)) = S(Z)
bin2peano(Cons(B0,Cons(a,x))) = doubleP(bin2peano1(Cons(a,x)))
bin2peano(Cons(B1,Cons(a,x))) = S(doubleP(bin2peano1(Cons(a,x))))

bin2peano1(Cons(B0,x)) = doubleP(bin2peano1(x))
bin2peano1(Cons(B1,x)) = S(double(bin2peano2(x)))

bin2peano2(Nil)        = Z
bin2peano2(Cons(B0,x)) = doubleP(bin2peano1(x))
bin2peano2(Cons(B1,x)) = S(double(bin2peano2(x)))

double(Z)    = Z
double(S(x)) = S(S(double(x)))

doubleP(S(Z))    = S(S(Z))
doubleP(S(S(x))) = S(S(S(S(double(x)))))
		    
-- Does specialization of function help in this case?