anchor.diff:     (format nil "cp -r ~A ~A"
   	   (princ-to-string from)
   	   (princ-to-string to))))
  -
  -(defparameter *address-cache-operation* :symlink)
   
   (defgeneric cache-repository-from-address (repository-address repository target-directory)
     (:documentation "Cache the given repository from repository-address to target-directory.
  
positive.code: 	    (loop 
  	       for cld-repository in *cld-repositories*
  	       while (not cld)
  	       do (progn
  		    (setf cld (find-cld cld-repository
  					library-name))
  		    (when cld
  
negative.code: (defparameter *repositories-directory*
    (asdf:system-relative-pathname :cldm "cache/repositories/"))
  
  (defparameter *address-cache-operation* :symlink "What to do when caching a local file system directory. Can be either :symlink or :copy (copy the directory recursively). Default is :symlink")
  
  (defparameter *github-cld-repository*
    `(make-instance 'http-cld-repository
  		  :name "Github repository"
  		  :url "http://mmontone.github.io/cldm-repo/cld"))
  
  (defparameter *cld-repositories* (list *github-cld-repository*))
  
  (defun call-with-repositories-directory (pathname function)
    (let ((*repositories-directory* pathname))
  