Reactive programming in Python ?

pca pierre.carbonnelle at
Sat Apr 17 10:13:21 CEST 2010

On Apr 17, 8:09 am, Stefan Behnel <stefan... at> wrote:
> pca, 16.04.2010 22:02:
> > On Apr 16, 8:28 pm, Stefan Behnel wrote:
> >> pca, 16.04.2010 17:18:
> >>> In fact, I have seeded an open-source project, Yoopf, that enables
> >>> programming by formula within Python, with the goal of dramatically
> >>> accelerating the development of the model view in the MVC model.
> >> Looks like the example on the main page would work better with the "any"
> >> builtin than with the "sum" builtin.
> > I'm not sure what you mean.  The example formula in the main page of
> >http://www.yoopf.orgcalculates the total amount of an order as the
> > sum of the amount of each order line: why the 'any' ?
> I guess I misinterpreted the phrase "only when one of its order line has
> been added or deleted" as meaning that a change to any of the amounts would
> trigger an event. It wasn't clear to me that the example actually presented
> a calculation that would be evaluated based on that event.
> You might want to give potential users a better idea of what this tool
> does. Neither your announcement nor the homepage made that clear to me.
> Stefan

Thanks for the feedback, Stefan.  I have rephrased the sentence as
follows.  Is that more clear ?

"For example, this formula is fed to the library to define the total
amount of each Order object as the sum of the amount of its order

"Order.amount = sum(Order.order_lines.amount)

"At the end of a transaction, the formula calculator is run : it will
calculate the formula only for the Order objects that need
recalculation (e.g because one of its order line has been added or
deleted, or the amount of a line has been changed).

Pierre C.

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