anchor.diff:  
   (defvar *cmd-map* (make-hash-table))
   (defvar *cmd-priority-array* (make-array 0))
  -(defvar *cmd-groups-map* (make-hash-table))
   
   (defclass command-handler ()
     ((%identifier :initarg :identifier :initform (error "Identifier required.") :accessor identifier)
  
positive.code:                       :arguments () :priority :LAST
                        :docstring "Catchall command handler for when no command matched.")
  
  (defun escape-regex-symbols (string)
    (cl-ppcre:regex-replace-all "([\\\\\\^\\$\\.\\|\\?\\*\\+\\(\\)\\[\\]\\{\\}])" string '("\\" 0)))
  
  (defmacro define-group (name &key documentation pattern)
    (unless pattern
      (setf pattern (format NIL "^~a(.*)" (escape-regex-symbols name))))
    )
  
  (defmacro define-command (name (&rest args) (&key authorization documentation (eventvar 'event) module-name (modulevar 'module) pattern priority) &body body)
    )
  
negative.code:   "Remove the COMMAND-HANDLER associated with the given IDENTIFIER."
    (assert (symbolp identifier) () "IDENTIFIER has to be a symbol.")
    (remhash identifier *cmd-map*)
    (generate-command-priority-cache)
    identifier)
  
  (defun set-command-function (identifier cmd-pattern handler-function &key (arguments () a-p) (priority (length cmd-pattern)) docstring)
    "Set a new handler function for a command pattern.
  
  IDENTIFIER       --- A symbol identifying your handler.
  