anchor.diff:  
   (defmacro opf (operator variable &rest arguments)
     "OPF is a generic operate-and-store macro, along the lines of INCF and DECF,
  -  but allowing for any operation.  For example:
  -    (opf #'+ foo 42)
  -  does something like
  -    (incf foo 42)
  -  but you could also do
  -    (opf #'+ foo 1 2 3 4 5)
  -  with it doing the obvious thing, whereas you cannot do
  -    (incf foo 1 2 3 4 5)
  -  in any Common Lisp I have used."
  +but allowing for any operation.  For example:
  +  (opf #'+ foo 42)
  +does something like
  +  (incf foo 42)
  +but you could also do
  +  (opf #'+ foo 1 2 3 4 5)
  +with it doing the obvious thing, whereas you cannot do
  +  (incf foo 1 2 3 4 5)
  +in any Common Lisp I have used."
     `(setf ,variable
            (funcall ,operator ,variable ,@arguments)))
   
  
positive.code: 
  (defun tms-values (time-multiseries positions)
    "This function returns a list of the values in a time series or multiseries
    at the specified positions.  A time multiseries is represented as a list of
    arrays with identical dimensions, where each array represents a single time
    step's entire data.  A time series is represented as a list.  The first value
    in each position is the time position."
    (assert (listp positions))
    (setf positions (mapcar #'(lambda (position)
                                (if (listp position)
  
negative.code: 
  (defmacro do-until (conditional &rest body)
    "A DO-UNTIL loop construct; it operates like do {BODY} while (! CONDITIONAL)
  construct in the C programming language."
    `(do-while (not ,conditional)
       ,@body))
  
  (defmacro for (initial conditional step-action &rest body)
    "A FOR macro, much like the ``for'' in the C programming language.
  A simple example:
    (for ((i 0))
         (< i 10)
         (incf i)
      (format t \"~%~A\" i))
  prints the numbers from 0 through 9, each on their own lines.
  Generally this should not be used, but instead the native looping methods."
    `(let ,initial
       (while ,conditional
         (prog1 (progn ,@body) ,step-action))))
  