diff --git a/TODO b/TODO
index e37e1be8..40f9f43c 100644
--- a/TODO
+++ b/TODO
@@ -7,6 +7,16 @@ Find out how to hook-up sc-expand in eval/apply.
 ** bugs
 See bugs/
 ** run PEG
+*** Simple Guile test:
+    make guile-peg
+*** PEG on Mes does not work yet:
+    make peg
+**** v define-syntax-rule
+**** v assq-ref
+**** v assq-set!
+**** datum->syntax
+**** syntax->datum
+**** syntax-case
 ** parse C using PEG 
 http://piumarta.com/software/peg/
 ** implement core primitives: DONE
diff --git a/scm.mes b/scm.mes
index 214d26e1..9f8ce9b3 100755
--- a/scm.mes
+++ b/scm.mes
@@ -107,7 +107,19 @@
         ((and (pair? p) (eq? (car p) '*lambda*)))
         (#t #f)))
 
+(define (assq-set! alist key val)
+  (let ((entry (assq key alist)))
+    (cond (entry (set-cdr! entry val)
+                 alist)
+          (#t (cons (cons key val) alist)))))
+
+(define (assq-ref alist key)
+  (let ((entry (assq key alist)))
+    (if entry (cdr entry)
+        #f)))
+
 (define assv assq)
+
 (define (memq x lst)
   (cond ((null? lst) #f)
         ((eq? x (car lst)) lst)
diff --git a/test.mes b/test.mes
index 23e126df..a4d0567a 100644
--- a/test.mes
+++ b/test.mes
@@ -132,6 +132,10 @@
 (pass-if "memq" (sequal? (memq 'b '(a b c)) '(b c)))
 (pass-if "memq" (seq? (memq 'd '(a b c)) #f))
 (pass-if "member" (sequal? (member '(a) '((a) b c)) '((a) b c)))
+(pass-if "assq-ref" (seq? (assq-ref '((b . 1) (c . 2)) 'c) 2))
+(pass-if "assq-ref 2" (seq? (assq-ref '((b . 1) (c . 2)) 'a) #f))
+(pass-if "assq-set!" (sequal? (assq-set! '((b . 1)) 'a 0) '((a . 0) (b . 1))))
+(pass-if "assq-set! 2" (sequal? (assq-set! '((a . 0)) 'a 1) '((a . 1))))
 
 ;; works, but debugging is foo
 ;; (cond ((defined? 'loop2)
@@ -191,7 +195,7 @@
 (pass-if "closure 3" (sequal? (x) '(0 0)))
 
 (pass-if "closure 4 "
-  (seq? (begin
+  (seq? (let ()
           (let ((count (let ((counter 0))
                          (lambda ()
                            counter))))
@@ -200,7 +204,7 @@
 
 (pass-if "closure 5 "
          (seq?
-          (begin
+          (let ()
             (define name? 2)
             (define (foo)
               (define name? 0)
@@ -210,7 +214,7 @@
 
 (pass-if "closure 6 "
          (seq?
-          (begin
+          (let ()
             (define foo
               (lambda ()
                 (define name? symbol?)