p 1) ((struct-ref p 2) value))
                           ...)
               body body* ...)))))))

(define* (fluid->parameter fluid #:optional (conv (lambda (x) x)))
  "Make a parameter that wraps a fluid.

The value of the parameter will be the same as the value of the fluid.
If the parameter is rebound in some dynamic extent, perhaps via
`parameterize', the new value will be run through the optional CONV
procedure, as with any parameter.  Note that unlike `make-parameter',
CONV is not applied to the initial value."
  (make-struct/no-tail
   <parameter>
   (case-lambda
    (() (fluid-ref fluid))
    ((x) (let ((prev (fluid-ref fluid)))
           (fluid-set! fluid (conv x))
           prev)))
   fluid conv))