anchor.diff:  
   (defun default-from-type (typecode)
     (ecase (typecode-kind typecode)
  -    ((:tk_ushort :tk_short :tk_ulong :tk_long :tk_float :tk_double 
  -      :tk_octet :tk_longlong :tk_ulonglong :tk_longdouble) 
  +    ((:tk_ushort :tk_short :tk_ulong :tk_long :tk_float :tk_double
  +      :tk_octet :tk_longlong :tk_ulonglong :tk_longdouble)
        0)
       ((:tk_boolean) nil)
       ((:tk_char) #\Space)
  
positive.code:       (let* ((typecode (if (stringp id-or-typecode)
                             (get-typecode id-or-typecode)
                           id-or-typecode))
               (fields 
                (multiple-value-bind (kind params)
                    (type-expand typecode)
                  (assert (eq kind :tk_struct))
  
negative.code: ;; Interface:
  (defun struct-typecode (id name &rest fields)
    (make-typecode :tk_struct
                   id
                   (string (or name ""))
                   (coerce (loop for (name type) on fields by #'cddr
                               collect (list (string name) type))
  