On Feb 15, 2013, at 11:45 AM, Derek Atkins <warl...@mit.edu> wrote: > John Ralls <jra...@ceridwen.us> writes: > >> On Feb 15, 2013, at 11:08 AM, Derek Atkins <warl...@mit.edu> wrote: >> >>> John Ralls <jra...@ceridwen.us> writes: >>> >>>> Gnucash isn't written that way, but it can be fixed. It just takes >>>> someone to do the work -- though if we want it done in our lifetimes, >>>> several someones. >>> >>> Right, that was my point... GnuCash isn't written as an MVC. And even >>> if it was, it's hard to say how the V would interact with the M and C >>> interactively... >> >> Why hard to say? MVC isn't exactly cutting-edge design. It's been >> around since 1988 and 7 years later GoF thought it so well-understood >> that it's the "how to use patterns" example in the introduction. > > Well, the point is that every time the user leaves a field you need to > parse all the input fields and process them in the controller/model as > part of the validation, even if the user hasn't asked to 'save' yet. > > I guess it all depends on your controller APIs. (In the RoR world this > is harder to do, because the view is in the browser, but the model and > controllers are on the server -- and there is no "verify this model" API > in the controller. At least not directly. The client-side-validations > gem adds some support for this).
We already do that for the account type listbox: We connect to a signal (don't know offhand which one) in the parent accounts GtkTreeView that tells us that the user has selected a parent account, retrieve that account, run xaccAccountGetCompatibleTypes() on it, and populate the account type listbox with the result. That's a pretty standard way for UI View objects to communicate with their controller objects, though there are others. Wx has a specific "Validator" class that lets you register a callback to test control input as it happens. It also has a signals mechanism (which they rather confusingly call Events) to support other interactivity needs. Qt is well-known for its "signals and slots" feature, which I imagine is used for this purpose much like Gtk's signals are, but I've never written anything for Qt so I don't actually know. Regards, John Ralls _______________________________________________ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
