Re: Recursive elements in DSSSL

[Brandon Ibach <bibach@xxxxxxxxxxxxxx>]

Quoting Stephane Bortzmeyer <bortzmeyer@xxxxxxxxxx>:
> On Mon, Mar 06, 2000 at 03:31:38PM -0600, Brandon Ibach wrote:
> >    The value of 'n' should be the node (element) whose "section depth"
> > you want to calculate.
> 
> I must confess that I wasn't able to program something with these
> indications (and "ancestors" do not exist in jade 1.2). Any actual
> complete code?
> 
   Here ya go...

-Brandon :)

<!doctype section [
<!element section - - (section|#PCDATA)*>
]>
<section>
  <section>
    <section></section>
  </section>
  <section>
    <section>
      <section></section>
    </section>
  </section>
</section>

<!doctype style-sheet PUBLIC "-//James Clark//DTD DSSSL Style Sheet//EN">
<style-specification id=section>

(define debug
  (external-procedure "UNREGISTERED::James Clark//Procedure::debug"))

(declare-flow-object-class element
  "UNREGISTERED::James Clark//Flow Object Class::element")
(declare-flow-object-class formatting-instruction
  "UNREGISTERED::James Clark//Flow Object Class::formatting-instruction")

(declare-characteristic preserve-sdata?
  "UNREGISTERED::James Clark//Characteristic::preserve-sdata?" #f)

(define (ancestors nl) (node-list-map (lambda (snl)
  (let loop ((cur (parent snl)) (result (empty-node-list)))
       (if (node-list-empty? cur) result
           (loop (parent cur) (node-list cur result))))) nl))

; These functions are here only for the code that inserts
; newlines to compensate for the parser stripping them out
(define (node-list-last nl) (let loop ((n nl) (r (empty-node-list)))
  (if (node-list-empty? n) r (loop (node-list-rest n) (node-list-first n)))))

(define (child-class nl proc) (let ((c (children nl)))
  (and (not (node-list-empty? c)) (node-property 'classnm (proc c)))))

(define (first-class nl) (child-class nl node-list-first))
(define (last-class  nl) (child-class nl node-list-last))

(root (sosofo-append (process-children)
        (make formatting-instruction data: "\U-000D;\U-000A;")))

(element section (let ((n (current-node)))
  (make element
    attributes: (list (list "depth" (number->string (node-list-length
                  (select-elements (ancestors n) (gi n))))))
; This (and the one after process-children) re-inserts newlines
    (if (equal? (first-class n) 'data-char)
        (make formatting-instruction data: "\U-000D;\U-000A;") (empty-sosofo))
    (process-children)
    (if (not (equal? (last-class n) 'element)) (empty-sosofo)
        (make formatting-instruction data: "\U-000D;\U-000A;")))))

</style-specification>