diff -Nrc spiffy.orig/spiffy-base.scm spiffy/spiffy-base.scm
*** spiffy.orig/spiffy-base.scm	Fri Nov 11 20:54:49 2005
--- spiffy/spiffy-base.scm	Mon Dec 19 23:59:45 2005
***************
*** 179,186 ****
    (if (pair? proc)
        (let ([a (assq type content-transporters)])
  	(if a
! 	    (set-cdr! a proc)
! 	    (set! content-transporters (alist-cons type proc content-transporters)) ) )
        (or (and-let* ([a (assq type content-transporters)]) (cdr a))
  	  default-content-transporter) ) )
  
--- 179,186 ----
    (if (pair? proc)
        (let ([a (assq type content-transporters)])
  	(if a
! 	    (set-cdr! a (car proc))
! 	    (set! content-transporters (alist-cons type (car proc) content-transporters)) ) )
        (or (and-let* ([a (assq type content-transporters)]) (cdr a))
  	  default-content-transporter) ) )