chickadee » srfi-217 » iset-adjoin

The `iset-adjoin` procedure returns a newly allocated iset that contains all the values of iset, and in addition each element unless it is already equal to one of the existing or newly added members.

Examples:

   (iset->list (iset-adjoin (iset 1 3 5) 0)) ⇒ (0 1 3 5)