Working with Datatypes (Cont)

insert (i, NULL) = L(i) |

insert (i, L(j)) =

if i < j then I(j,L(i),NULL)

else I(j,NULL,L(i)) |

insert (i, I(j, ls, rs)) =

if i=j then I(j, ls, rs)

else if i < j then I(j, insert(i,ls),rs)

else I(j, ls, insert(i, rs));