diff --git a/Makefile b/Makefile
index 89584c81..2000cd2e 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,6 @@ PICRIN_OBJS = \
 	$(PICRIN_SRCS:.c=.o)
 PICRIN_LIBS = \
 	piclib/picrin/macro.scm\
-	piclib/picrin/experimental/lambda.scm\
 	piclib/picrin/syntax-rules.scm\
 	piclib/picrin/test.scm
 
diff --git a/contrib/50.destructuring-bind/lambda.scm b/contrib/50.destructuring-bind/lambda.scm
new file mode 100644
index 00000000..c3fc9872
--- /dev/null
+++ b/contrib/50.destructuring-bind/lambda.scm
@@ -0,0 +1,24 @@
+(define-library (picrin destructuring-bind)
+  (import (picrin base)
+          (picrin macro))
+
+  (define-syntax (destructuring-bind formal value . body)
+    (cond
+     ((variable? formal)
+      #`(let ((#,formal #,value))
+          #,@body))
+     ((pair? formal)
+      #`(let ((value #,value))
+          (destructuring-bind #,(car formal) (car value)
+            (destructuring-bind #,(cdr formal) (cdr value)
+              #,@body))))
+     ((vector? formal)
+      ;; TODO
+      (error "fixme"))
+     (else
+      #`(if (equal? #,value '#,formal)
+            (begin
+              #,@body)
+            (error "match failure" #,value '#,formal)))))
+
+  (export destructuring-bind))
diff --git a/contrib/50.destructuring-bind/nitro.mk b/contrib/50.destructuring-bind/nitro.mk
new file mode 100644
index 00000000..101e7bc7
--- /dev/null
+++ b/contrib/50.destructuring-bind/nitro.mk
@@ -0,0 +1 @@
+CONTRIB_LIBS += $(wildcard contrib/50.destructuring-bind/*.scm)
diff --git a/piclib/picrin/experimental/lambda.scm b/piclib/picrin/experimental/lambda.scm
deleted file mode 100644
index 8bbcce40..00000000
--- a/piclib/picrin/experimental/lambda.scm
+++ /dev/null
@@ -1,37 +0,0 @@
-(define-library (picrin experimental lambda)
-  (import (picrin base)
-          (picrin macro))
-
-  (define-syntax (destructuring-let formal value . body)
-    (cond
-     ((variable? formal)
-      #`(let ((#,formal #,value))
-          #,@body))
-     ((pair? formal)
-      #`(let ((value #,value))
-          (destructuring-let #,(car formal) (car value)
-            (destructuring-let #,(cdr formal) (cdr value)
-              #,@body))))
-     ((vector? formal)
-      ;; TODO
-      (error "fixme"))
-     (else
-      #`(if (equal? #,value '#,formal)
-            (begin
-              #,@body)
-            (error "match failure" #,value '#,formal)))))
-
-  (define-syntax (destructuring-lambda formal . body)
-    #`(lambda args
-        (destructuring-let #,formal args #,@body)))
-
-  (define-syntax (destructuring-define formal . body)
-    (if (variable? formal)
-        #`(define #,formal #,@body)
-        #`(destructuring-define #,(car formal)
-            (destructuring-lambda #,(cdr formal)
-              #,@body))))
-
-  (export (rename destructuring-let let)
-          (rename destructuring-lambda lambda)
-          (rename destructuring-define define)))