Well, I'm back to the same failed unit tests as the develop branch

and I *feel* that the intern code is better. But it's not without
problems and I don't think I can release at this. But it may be
ready to merge back.

lisp/documentation.lisp

@@ -3,6 +3,31 @@
 ;; `nth` (from `nth.lisp`)
 ;; `string?` (from `types.lisp`)
 
+(set! nil? (lambda 
+          (o) 
+          "`(nil? object)`: Return `t` if object is `nil`, else `t`."
+          (= o nil)))
+
+(set! member? (lambda
+            (item collection)
+            "`(member item collection)`: Return `t` if this `item` is a member of this `collection`, else `nil`."
+            ;; (print (list "In member? item is " item "; collection is " collection))
+            ;; (println)
+            (cond
+              ((= nil collection) nil)
+              ((= item (car collection)) t)
+              (t (member? item (cdr collection))))))
+
+;; (member? (type member?) '("LMDA" "NLMD"))
+
+(set! nth (lambda (n l) 
+    "Return the `n`th member of this list `l`, or `nil` if none."
+    (cond ((= nil l) nil)
+        ((= n 1) (car l))
+        (t (nth (- n 1) (cdr l))))))
+
+(set! string? (lambda (o) "True if `o` is a string." (= (type o) "STRG") ) )
+
 (set! documentation (lambda (object)
     "`(documentation object)`:  Return documentation for the specified `object`, if available, else `nil`."
    (cond ((member? (type object) '("FUNC" "SPFM"))
@@ -15,3 +40,7 @@
 
 (set! doc documentation)
 
+(documentation apply)
+
+;; (documentation member?)
+