anchor.diff:  
   (defun all-command-names ()
     (alexandria:hash-table-keys *command-table*))
  -
  -(defun exist-command-p (str)
  -  (if (find-command str) t nil))
  
positive.code:                         (car arg-descripters))
                   (apply #',fn-name ,arguments)))))))
  
  (defun find-command (name)
    (car (gethash name *command-table*)))
  
  (defun find-command-symbol (name)
    (cdr (gethash name *command-table*)))
  
negative.code: (in-package :lem)
  
  (export '(define-command
            exist-command-p))
  
  (defvar *command-table* (make-hash-table :test 'equal))
  