Re: high level application frameworkl

[Daniel Kasak <dkasak nusconsulting com au>]

Dirk Koopman wrote:

> On Tue, 2006-07-25 at 09:37 +1000, Daniel Kasak wrote:
>   
> > Dirk Koopman wrote:
> >     
> > > For many years (about 26) I have used an "application framework" of my
> > > own devising (in various incarnations) for separating "business
> > > logic" [ugh] and data manipulation, completely, from visual
> > > representation on "curses" based terminals. 
> > >
> > > It allows programmers to say things like: take these data fields
> > >       
> > Gtk2::Ex::DBI ... links to ...
> >     
>
> Who says there is any SQL (or ISAM or files) involved?
>   

The bit about 'take these data fields' said to me that you'd be storing
stuff in a database. If you're not, then apologies ...

> > >  then tell me if these values are
> > > entered or those keys are pressed;
> > >       
> > Either connect to the 'changed' signal of each widget and do things
> > while the user is inputting data, or pull all the values at once when
> > the data entry is complete and the user hits 'apply'. With Gtk2::Ex::DBI
> > you can do all this by defining a 'before_apply' callback which is run
> > before the record is applied.
> >     
>
> And at this point it all goes pear shaped, because we are thinking the
> wrong way up. Also I want fine grained control *during* the form and I
> don't wish to get into the minutia of gtk style callbacks (under the
> hood things will be calling back like billy-ho) but for the programmer
> this must all be seamless (and very, very easy).
>   

Huh?

This is pretty strange logic. If the programmer doesn't tie everything
together, then who exactly is going to do it? If you want fine-grained
control over things, then that will require you to write some code, yes.
The point is to do it once, correctly, and reuse the code.

> The programmer thinks in terms of the field (or data if you will); he
> isn't interested, nor does he know, that it will indeed be implemented
> with the sort of callback you describe.

Huh?

> The Gtk part is the widget set
> that *implements* the data model and programming abstraction that I am
> trying to describe.
>   

Gtk isn't implementing any data model in a hurry. It's a widget toolkit,
and knows *very* little about data. Your data model should be provided
solely by *you*. You can build custom widgets to do validation on data
as the user enters it, but again, this is provided by *you*. Gtk is for
building the GUI. Only. What you seem to be more interested in is
managing data.

-- 
Daniel Kasak
IT Developer
NUS Consulting Group
Level 5, 77 Pacific Highway
North Sydney, NSW, Australia 2060
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email: dkasak nusconsulting com au
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