[GNC] Scheduled Transaction Calculations

[Fross, Michael]

Thanks John.  I'll give is a shot and report back.

Michael

On Fri, Nov 1, 2019 at 2:34 PM John Ralls <jralls at ceridwen.us> wrote:

>
>
> > On Nov 1, 2019, at 9:36 AM, Fross, Michael <michael at fross.org> wrote:
> >
> > Hello all,
> >
> > I have a scheduled transaction that I pay monthly which is a fixed amount
> > per day.  I'd love to be able to have is automatically entrer based on
> the
> > number of days per month.  I pay on the 1st (or the first business day
> > after that) so basically I'd like to use the following formula:
> >
> > Amount = NumDaysInPreviousMonth * AmountPerDay
> >
> > I looked through the guide
> > <https://wiki.gnucash.org/wiki/Scheduled_Transactions> and didn't see
> > anything.  It references fin.scm (link throws a 404 by the way) but I
> > didn't see anything here that calculated the number of days in the
> previous
> > month (but perhaps I missed it in the SCM code.)
> >
> > This seems like a simple use case, am I missing something? Perhaps I'll
> > need to write a function in fin.scm that can return the number of days
> in a
> > provided month.  No idea how to use scheme, but I'm sure I can figure it
> > out.
> >
> > Thoughts?
>
> I fixed the link.
>
> The closest functions in GnuCash would be gnc:get-start-prev-month and
> gnc:get-end-prev-month. They return time64 so you'd divide the difference
> by 86400 (the number of seconds in a day) after adding in 1 second to
> compensate for gnc:get-start-prev-month's returning the first second of the
> month rather than the last second of the month before.
>
> You could try adding this to fin.scm:
>
> (load-from-path "gnucash/app-utils")
> (define (gnc:days-in-prev-month) (/ ( + 1 (- (gnc:get-end-prev-month)
> (gnc:get-start-prev-month)))) 86400))
>
> Then use
>   days-in-prev-month() * AmountPerDay
> in your scheduled transaction. Replace "AmountPerDay" with the actual
> numeric amount or the Since Last Run dialog will ask for the amount every
> month.
>
> I've never actually tried doing anything like that, but it might work.
>
> Regards,
> John Ralls
>
>
>
>