diff --git a/forge/sf.lisp b/forge/sf.lisp
index 9f56d1c..b1a7cc6 100644
--- a/forge/sf.lisp
+++ b/forge/sf.lisp
@@ -5,7 +5,8 @@
 (defpackage :scopes/forge/sf
   (:use :common-lisp)
   (:local-nicknames (:iter :scopes/util/iter))
-  (:export #:*stack*
+  (:export #:*input* #:*stack*
+           #:proc-list #:proc-input
            #:add
            #:pushd #:popd))
 
@@ -15,19 +16,35 @@
 (in-package :scopes/forge/sf)
 
 (defvar *stack* nil)
+(defvar *input* nil)
 
-;;;; builtins
+;;;; core definitions
+
+(defun proc-list (lst)
+  (setf *input* (make-instance 'iter:list-iterator :data lst))
+  (proc-input))
+
+(defun proc-input ()
+  (let ((inp *input*))
+    (do ((item (iter:next inp) (iter:next inp)))
+        ((null item))
+      (proc-item item))))
+
+(defun proc-item (item)
+  (typecase item
+    (symbol (funcall item))
+    (t (pushd item))))
 
 (defun reg2 (sym fn)
   (setf (fdefinition sym) #'(lambda ()
     (pushd (funcall fn (popd) (popd))))))
 
-(reg2 'add #'+)
-
-;;;; core definitions
-
 (defun pushd (v)
   (push v *stack*))
 
 (defun popd ()
   (pop *stack*))
+
+;;;; builtins
+
+(reg2 'add #'+)
diff --git a/test/test-sf.lisp b/test/test-sf.lisp
index 79709f3..23d68fb 100644
--- a/test/test-sf.lisp
+++ b/test/test-sf.lisp
@@ -26,6 +26,8 @@
   (forge:pushd 2)
   (forge:add)
   (== (forge:popd) 6)
+  (forge:proc-list '(4 2 forge:add))
+  (== (forge:popd) 6)
   ;(forge:exec-str "4 2 +")
   ;(== (car (forge:dstack)) 6))
   (t:show-result))
diff --git a/util/iter.lisp b/util/iter.lisp
index a940626..f40cbb1 100644
--- a/util/iter.lisp
+++ b/util/iter.lisp
@@ -5,9 +5,26 @@
 
 (defpackage :scopes/util/iter
   (:use :common-lisp)
-  (:export #:list-iterator))
+  (:export #:current #:next 
+           #:list-iterator))
 
 (in-package :scopes/util/iter)
 
+;;;; iterators
+
+(defgeneric next (it))
+(defgeneric current (it))
+
 (defclass list-iterator ()
-  ((data :reader data :initarg :data :initform nil)))
+  ((data :reader data :initarg :data :initform nil)
+   (cur :accessor cur)))
+
+(defmethod initialize-instance :after ((it list-iterator) &key &allow-other-keys)
+  (setf (cur it) (cons nil (data it))))
+
+(defmethod next ((it list-iterator))
+  (pop (cur it))
+  (current it))
+
+(defmethod current ((it list-iterator))
+  (car (cur it)))