keep functional seq (pointer) definition in separate file for reference

forge/seq-functional.lisp

@@ -0,0 +1,50 @@
+;;; cl-scopes/forge/seq-functioinal.list
+;;; a functional closure-based implementation of 
+;;; sequence with three pointers
+
+;;; not used, stored here for later reference
+
+(defun make-seq ()
+  (let* ((start (list nil))
+         (cur start)
+         (end start)
+         (args (list start cur end)))
+    #'(lambda (fn) 
+        (setf args (apply fn args)))))
+
+(defun seq-all (seq)
+  (let (rv)
+    (funcall seq #'(lambda (start cur end) 
+                     (setf rv (cdr start))
+                     (list start cur end)))
+    rv))
+
+(defun seq-cur (seq)
+  (let (rv)
+    (funcall seq #'(lambda (start cur end) 
+                     (setf rv (car cur))
+                     (list start cur end)))
+    rv))
+
+(defun seq-end (seq)
+  (let (rv)
+    (funcall seq #'(lambda (start cur end) 
+                     (setf rv (car end))
+                     (list start cur end)))
+    rv))
+
+(defun seq-next (seq)
+  (let (rv)
+    (funcall seq #'(lambda (start cur end) 
+                     (pop cur)
+                     (setf rv (car cur))
+                     (list start cur end)))
+    rv))
+
+(defun seq-add (seq v)
+    (funcall seq #'(lambda (start cur end)
+                     (setf (cdr end) (list v))
+                     (pop end)
+                     (list start cur end)))
+    nil)
+