<fixnum> typeType of fixnum values.
<fixnum>: <fixnum> type-constructor objValidate obj as object of type <fixnum> and return it.
<fixnum>: <boolean> type-predicate objThe type predicate is fixnum?. Return #t if obj is a
<fixnum> object, otherwise return #f.
<fixnum>: <non-negative-fixnum> hash-function thisThe hash function is fixnum-hash.