diff --git a/src/main/resource.cl b/src/main/resource.cl
index d8702ae..8b37f36 100644
--- a/src/main/resource.cl
+++ b/src/main/resource.cl
@@ -19,29 +19,68 @@
 
 (defgeneric resource-allowed-methods (resource))
 
-(defgeneric access-resource (resource request))
+(defgeneric access-resource (resource request)
+  (:argument-precedence-order request resource))
 
-(defgeneric access-resource-using-method (resource request method))
+(defgeneric access-resource-using-method (resource request method)
+  (:argument-precedence-order method request resource))
 
 (defmethod access-resource ((resource resource) request)
   (let ((method (request-method request))
 	(allowed-methods (resource-allowed-methods resource)))
     (if (member method allowed-methods)
 	(access-resource-using-method resource request method)
-	(create-response request
-			 +HTTP-Code-Method-Not-Allowed+
-			 (make-instance 'simple-entity
-					:allow allowed-methods)))))
+	(error 'clash-error :code +HTTP-Code-Method-Not-Allowed+
+	       :entity-initargs (list :allow allowed-methods)))))
 
-(defclass simple-resource (resource)
-  ((content :initarg :content :accessor simple-resource-content)
-   (allowed-methods :allocation :class :initform '(:GET)
+(defclass static-resource (resource)
+  ((entity :initarg :entity :accessor static-resource-entity)
+   (allowed-methods :allocation :class :initform '(:GET :HEAD)
 		    :reader resource-allowed-methods)))
 
 (defmethod access-resource-using-method
-    ((resource simple-resource) request (method (eql :GET)))
+    ((resource static-resource) request (method (eql :GET)))
   (create-response request +HTTP-Code-OK+
 		   :entity
-		   (make-instance 'simple-entity
-				  :body
-				  (simple-resource-content resource))))
+		   (static-resource-entity resource)))
+
+(defmethod access-resource-using-method
+    ((resource static-resource) request (method (eql :HEAD)))
+  (create-response request +HTTP-Code-OK+
+		   :entity
+		   (static-resource-entity resource)))
+
+(defclass dynamic-resource (resource)
+  ((allowed-methods :initarg :allowed-methods
+		    :initform '(:GET :HEAD)
+		    :reader resource-allowed-methods)
+   (generator :initarg :generator :reader dynamic-resource-generator)))
+
+(defmethod access-resource-using-method
+    ((resource dynamic-resource) request method)
+  (funcall (dynamic-resource-generator resource) resource request method))
+
+(defclass dynamic-form-resource (dynamic-resource)
+  ((processor :initarg :processor :reader dynamic-form-resource-processor))
+  (:default-initargs :allowed-methods '(:GET :HEAD :POST)))
+
+(defmethod access-resource-using-method
+    ((resource dynamic-form-resource) request (method (eql :POST)))
+  (funcall (dynamic-form-resource-processor resource) resource request method))
+
+(defun parse-form-data (request)
+  (let* ((entity (request-entity request))
+	 (data (entity-body entity)))
+    (parse-query-part data 0 (length data))))
+
+(defmacro with-form-data (vars request &body body)
+  (loop with data-sym = (gensym)
+	for var in vars
+	collect
+	`(,var (cdr (assoc (symbol-name ',var) ,data-sym
+		           :test #'string-equal)))
+	into bindings
+	finally
+	(return `(let ((,data-sym (parse-form-data ,request)))
+		   (let ,bindings
+		     ,@body)))))