getting the attributes of a tag to qualify rewrites

I have the following rule:

(define (xform-person-name name-string)
    `(span *preorder* . ,(lambda (tag . content)
                           '(span ,name-string))))

But I need to make it more precise. I only want to rewrite span tags if 
the span tag has an attribute named "hsi" with value "overwrite_name", eg:

 Hello there,
    <span hsi=overwrite_name>blah blah</span>
    did you know that today was
    <span hsi=todays_date>blah blah blah</span>
    ?

Converting this to SXML is a snap with htmlprag:

(define (file->sxml file)
    (html->sxml (open-input-file file)))

(*TOP* (*DECL* DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 
Transitional//EN") "\n" (html "\n" "  " (head "\n" "    " (title "Point 
Mutation") "\n" "  ") "\n" "\n" "  " (body "\n" "    " (h1 "Point 
Mutation") "\n" "\n" "\n" "    Hello there,\n" "    " (span (@ (hsi 
"overwrite_name")) "blah blah") "\n" "    did you know that today was\n" 
"    " (span (@ (hsi "todays_date")) "blah blah blah") "\n" "    ?\n" 
"\n" "\n" "    " (hr) "\n" "    " (address (a (@ (href 
"mailto:[email protected]")) "U-MOKSHA\\metaperl")) "\n" (*COMMENT* " 
Created: Tue Jul 13 07:44:29 EDT 2004 ") "\n" (*COMMENT* " hhmts start 
") "\n" "Last modified: Tue Jul 13 07:47:44 EDT 2004\n" (*COMMENT* " 
hhmts end ") "\n" "  ") "\n") "\n")

I am trying to do HTML templating in the style of the Java framework 
called XMLC (xmlc.enhyrdra.net). I have implemented such templating for 
Perl via my HTML::Seamstress module, but now I want to use Scheme and 
need a little help getting the same things done under ssax/sxml.

Sorry for the chatty post, but just wanted to give a little background :)

-- 
  (let recur ((lis x) (k k)) 
    (if (zero? k) (values '() lis) 
	(receive (prefix suffix) (recur (cdr lis) (- k 1)) 
	  (values (cons (car lis) prefix) suffix))))) 



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