anchor.diff:    `(locally
       (declare #+SBCL (sb-ext:muffle-conditions sb-ext:compiler-note))
       ,@body))
  -
  -(defun write-bigendian-uint4 (uint out)
  -  (loop FOR offset FROM 24 DOWNTO 0 BY 8
  -        DO (write-byte (ldb (byte 8 offset) uint) out)))
  -
  -(defun read-bigendian-uint4 (in)
  -  (loop FOR offset FROM 24 DOWNTO 0 BY 8
  -        SUM (ash (read-byte in) offset)))
   
   (defmacro a.if (exp then else)
     `(let ((it ,exp))
  
positive.code:            fixnumize
             package-alias
             muffle
             write-bigendian-uint4
             read-bigendian-uint4
             a.if
             nlet
             with-open-output-file
  
negative.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;; unility function and macro
  (declaim (inline fixnumize))
  (defun fixnumize (n)
    (ldb (byte #.(integer-length most-positive-fixnum) 0) n))
  
  