[GNC] Reports: Help normalizing a list of gnc:monetary values

[Evelyn Yamanaka]

I'm trying to create a stacked bar chart graph where the total for
each period on the x-axis is 100%, so you can easily see trends in
changes in the proportion of individual accounts relative to the
total.

I'm using category-barchart.scm as a starting point, where account
balances are stored as a list of pairs (<account> <balance-list>) in
the variable all-data, and <balance-list> is a list of gnc:monetary
values (or something like that?) for each period on the x-axis.

I can get totals for each period with:

(let ((totals
        (map
          (lambda (l) (apply gnc:monetary+ l))
          (apply zip (map cadr all-data)))))
  (set! all-data-totals (list "Total" totals)))

However, I'm not sure how to divide gnc:monetary values by other
gnc:monetary values. I know I can add with:

(for-each
  (lambda (d)
    (let ((new-data (map gnc:monetary+ (cadr d) (cadr d))))
      (set! all-data-new
        (append all-data-new
                (list (car d) new-data)))))
  all-data)

But I'm not sure how to divide. Something like:
  (map gnc:monetary/ (cadr all-data-totals) (cadr d))

Of course, "gnc:monetary/" is undefined, and simply using "/" does not
work either. Is there any way to do this? Any help would be appreciated.

Thanks,
E