[Seaside] Metamodel and Form support

[Adrian Lienhard]

Hi Derek

At the moment there are several attribute classes (such as type, naming,
validationrules) which I use for my form support. I started using it for my
current project and it seams useful till now. What's still open, is how to
make the form enough flexible for nice custom design (but this is something
else...). And of corse, the metamodel could be improved (feedbacks very
wellcome!).

What would be interesting is to see how the metamodel can be used for other
components. E.g. the exsiting report-component. Or maybe it could be the
place to define security: Defining wich actions exsist and how the access is
restricted (wasn't it you, Derek, working on something like this?).

You can finde the current source here:
    http://www.adrian-lienhard.ch/files/squeak/Seaside-Metamodel.st
    http://www.adrian-lienhard.ch/files/squeak/Seaside-Form.st
    http://www.adrian-lienhard.ch/files/squeak/tableRowWithFix.cs
(#tableRowWith:with: had a tiny bug)

Please let me know if I should give some explanation how it works.

Btw, what is the status of your Web Calendar?

Adrian

_____________________
Adrian Lienhard
www.adrian-lienhard.ch
www.netstyle.ch

----- Original Message -----
From: "Derek Brans" <brans@nerdonawire.com>
To: <seaside@lists.squeakfoundation.org>
Sent: Tuesday, December 24, 2002 3:01 PM
Subject: Re: [Seaside] Metamodel and Form support


> Adrian,
> What is the status of the metamodel code?
>
> On Saturday, December 14, 2002, at 03:54 PM, Adrian Lienhard wrote:
>
> >
> > ----- Original Message -----
> > From: "Avi Bryant" <avi@beta4.com>
> > Sent: Saturday, December 14, 2002 10:06 PM
> >>
> > [...]
> >> I agree with Frank that the name "Page" is a confusing one - in a web
> >> application context, page has a very strong meaning already and it's
> >> best
> >> not to overload it.
> >
> > Yes, first I started with "AttributeSet" but then I thought that it
> > could be
> > missleading because it is not a kind of Set... but this might be less
> > confusing. Anyway, renaming is no problem.
> >
> >> But pages are also the part of your model I have
> >> trouble understanding - I think I see what you're trying to do (make
> >> the
> >> metamodel extensible to cover new types of information), but I'm not
> >> sure
> >> I like the way it's done.  Instead having a #Naming page and a #Type
> >> page
> >> for each attribute, I'd rather have a single Attribute class that had
> >> 'name type' as inst vars, containing AttributeName and AttributeType
> >> objects, for example.  Adding new types of information should be rare
> >> enough that inst variables could simply be added to Attribute as
> >> needed.
> >> This would do away with the nested Dictionaries in Metamodel, and would
> >> allow the Attribute class to provide more convenient ways of building
> >> up
> >> the structures
> >
> > Agreed. Maybe I wanted to be too general...
> >
> > [...]
> >> The way you have Fields working is interesting - not depending on the
> >> metamodel, but just loading it in as defaults.  Again, I can see the
> >> logic
> >> here, but actually I think it's more useful to just say "Attribute is
> >> how
> >> you control this form, and if you want to customize it, give it a
> >> different set of Attributes".  That is, right now you basically have
> >> two
> >> metamodels - the attribute and the one the form actually uses - and you
> >> translate between them.  I think it's more valuable to consistently use
> >> one - for example, Field>>value now looks something like
> >>
> >> model perform: selector
> >>
> >> whereas if you have a decent Attribute class, it should look like
> >>
> >> attribute valueForObject: model
> >>
> >> which is ultimately a lot more flexible.  If you keep two separate
> >> metamodels you'll either have to make them *both* that flexible (which
> >> isn't realistically gonna happen) or sacrifice the flexibility on one
> >> of
> >> them (in which case, why bother having the nice one?).
> >>
> >> These are just suggestions, of course - you do what works best for you,
> >> and if I don't like it, I'll just write an alternate implementation :).
> >
> > Thanks for the feedback and ideas. Actually, I would apreciate that
> > what I'm
> > doing can be used by others. I don't mind if you come up with an altered
> > version and say, "look, I've changed this and this". I am quite
> > open ;-).
> >
> > Adrian
> >
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> > http://lists.squeakfoundation.org/listinfo/seaside
> >
> >
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