Tail recursion

[Daniel Shane <daniel@xxxxxxxx>]

Hello,

I wanted to let all of you know that we (iNsu Innovations) have made
some small modifications to the scheme code which handles the docbook
area tag. This modification does not add any new features but greatly
improves the speed of the algorithm by at least a factor of 100 if not
more.

Unfortunately, we have a also a big problem. Everything seems to work
find with small to medium sized areas but with a big area, openjade will
segfault awfully. This arrises because it seems that one of our
functions is not considered tail recursive and we eventualy run out of
stack space. 

Now, I am no scheme expert but I have posted my scheme function and if
anyone could colaborate the fact that this function is tail recursive
then we have found a bug in openjades autodetection of tail recurisve
functions.

The frame that doesnt get popped is the call to append-sosofo. After
5062 calls to that function, we bomb out of stack space.
 
(define ($callout-linespecific-content$ indent line-numbers?)
  ;; Print linespecific content in a callout with line numbers
  (let ( (callouts-table  ($build-callouts-table$)))
    (make sequence
      ($line-start$ indent line-numbers? 1)
      (let loop ((kl (children (current-node)))
                 (co-table callouts-table)
                 (linecount 1)
                 (colcount 1)
                 (res (empty-sosofo)))
        (if (node-list-empty? kl)
            res
            (let* ((c (node-list-first kl))
                   (eol? (char=? (node-property 'char c
                                                default: #\U-0000)
#\U-000D))
                   (line-assoc (if (null? co-table) #f (car co-table))))
              (loop
               (debug (node-list-rest kl))
               (if eol?
                   (if (and line-assoc
                            (equal? linecount (car line-assoc)))
                       (if (null? co-table)
                           '()
                           (cdr co-table))
                       co-table)
                   co-table)
               (if eol?
                   (+ linecount 1)
                   linecount)
               (if eol?
                   1
                   (if (char=? (node-property 'char c
                                              default: #\U-0000)
#\U-0000)
                       colcount
                       (+ colcount 1)))
               (if eol?
                   (if (and line-assoc (equal? linecount (car
line-assoc)))
                     (sosofo-append res
                                      ($look-for-callout$ (cdr
line-assoc)
                                                             colcount
#t)
                                      (debug (process-node-list c))
                                      ($line-start$ indent line-numbers?
                                                    (+ linecount 1)))
                     (sosofo-append res
                                      (process-node-list c)
                                      ($line-start$ indent line-numbers?
                                                    (+ linecount 1))))
                   (if (and line-assoc (equal? linecount (car
line-assoc)))
                     (sosofo-append res
                                      ($look-for-callout$ (cdr
line-assoc)
                                                             colcount)
                                      (process-node-list c))
                     (sosofo-append res (process-node-list c)))))))))))


Any help would be greatly appreciated

Daniel Shane
--
daniel@xxxxxxxx
GNU/Linux developper
iNsu Innovations inc.


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