diff --git a/src/ikarus.boot b/src/ikarus.boot
index 38e4abc..42745a7 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.core.ss b/src/ikarus.core.ss
index 6fdc1ec..43ad9e4 100644
--- a/src/ikarus.core.ss
+++ b/src/ikarus.core.ss
@@ -111,22 +111,7 @@
       (error 'set-top-level-value! "~s is not a symbol" x))
     ($set-symbol-value! x v)))
  
-(primitive-set! 'symbol? (lambda (x) (symbol? x)))
   
-;(primitive-set! 'primitive?
-;  (lambda (x)
-;    (unless (symbol? x)
-;      (error 'primitive? "~s is not a symbol" x))
-;    (procedure? (primitive-ref x))))
-;
-;(primitive-set! 'primitive-ref
-;  (lambda (x)
-;    (unless (symbol? x)
-;      (error 'primitive-ref "~s is not a symbol" x))
-;    (let ([v (primitive-ref x)])
-;      (unless (procedure? v)
-;        (error 'primitive-ref "~s is not a primitive" x))
-;      v)))
 
 (primitive-set! 'primitive-set!
   (lambda (x v)
@@ -573,25 +558,6 @@
          (let ([v (make-vector n)])
            (loop v ls 0 n))))))
 
-(primitive-set! 'string
-  ;;; FIXME: add case-lambda
-  (letrec ([length
-            (lambda (ls n)
-              (cond
-               [(null? ls) n]
-               [(char? ($car ls)) (length ($cdr ls) ($fx+ n 1))]
-               [else (error 'string "~s is not a character" ($car ls))]))]
-           [loop 
-            (lambda (s ls i n)
-              (cond
-               [($fx= i n) s]
-               [else 
-                ($string-set! s i ($car ls))
-                (loop s ($cdr ls) ($fx+ i 1) n)]))])
-     (lambda ls
-       (let ([n (length ls 0)])
-         (let ([s (make-string n)])
-           (loop s ls 0 n))))))
  
 (primitive-set! 'list?
   (letrec ([race
diff --git a/src/ikarus.strings.ss b/src/ikarus.strings.ss
index cb0f042..a3ec388 100644
--- a/src/ikarus.strings.ss
+++ b/src/ikarus.strings.ss
@@ -1,10 +1,10 @@
 
 (library (ikarus strings)
   (export string-length string-ref string-set! make-string string->list string=?
-          string-append substring)
+          string-append substring string)
   (import 
     (except (ikarus) string-length string-ref string-set! make-string
-            string->list string=? string-append substring)
+            string->list string=? string-append substring string)
     (only (scheme) 
           $fx+ $fxsub1 $fxadd1 $char= $car $cdr
           $fxzero? $fx= $fx<= $fx< $fx>= $fx-
@@ -67,6 +67,26 @@
         make-string))
 
 
+  (define string
+    ;;; FIXME: add case-lambda
+    (letrec ([length
+              (lambda (ls n)
+                (cond
+                 [(null? ls) n]
+                 [(char? ($car ls)) (length ($cdr ls) ($fx+ n 1))]
+                 [else (error 'string "~s is not a character" ($car ls))]))]
+             [loop 
+              (lambda (s ls i n)
+                (cond
+                 [($fx= i n) s]
+                 [else 
+                  ($string-set! s i ($car ls))
+                  (loop s ($cdr ls) ($fx+ i 1) n)]))])
+       (lambda ls
+         (let ([n (length ls 0)])
+           (let ([s (make-string n)])
+             (loop s ls 0 n))))))
+
   (module (substring)
     (define fill
       (lambda (s d si sj di)