[self-interest] Model View Controller and the Observer pattern

Albertina Lourenci lourenci at lsi.usp.br
Mon Aug 27 14:18:39 UTC 2001

Jecel Assumpcao Jr wrote:

Dear Jecel:
Thanks for your prompt reply.My question would be obviously how to
reflect isomorphically  the highly interactive nature of the domain model
model + geometric modeling)  of my knowledge system into the "software
architectural level" (evidently of a hybrid nature = domain architecture +
software architecture). So the architecture level like a Janus face looks
into the domain model and  forward to the implementation level. The word
constraint in architecture is not good because the language of architecture
has the nature of the Chinese language. In Chinese any word can behave
as a verb, as a noun, as an adjective, as an adverb. It depends on the
context. So is architecture.If an architectonic element is chosen as a verb
(see the attachments mopst and mpstw)  this gives rise to the architectonic
party. So if you
stress the thermal comfort you have solar houses!!!!If you stress acoustics
you have Sydney Opera House, if you stress structure you have the
architecture of Luigi Pier Nervi!!!! Well a sustainable architecture in a
highly sustainable region would dovetail harmoniously all the architectonic
So the core data would consist of all the requirements of the architectonic
elements (better stored in a database due to complexity). Then we would
call from the database the data about the climate of the city, the
data of the bioregion and so on. In the application model, the designer
 has to input data specific for designing one ecobuilding in a specific site.

The model in the attachment has to add the electrical systems for sensors,
actuators to control the internal temperature of the building.

It is there independent of the use by clients and designers. It is naturally
decoupled from the "user interface". One is going to choose them
dependent on the budget and the resources available.

Moreover most of the time this data is also represented graphically (see
the attachment (substanceofthe function = substancia da função - beautifully
implemented in Self by Jecel!Heartfelt thanks!).The designer varies
the input according to the ecology of the behaviour of the human
being along its life cycle - baby ...until old age).
In reality there would be a team of designers responsible for each
architectonic element  presenting in the view model their specific
solution in a first step. So it would be interesting to present it
as in the MVC where the core data of an election (votes+ parties)
may be exhibited in the the view component as pie chart, bar
chart parliament, spreadsheet and so on. Differently from the
election case, of course each designer would choose different
data adapted to the ecobuilding. In the view component there
should be "a morph like the screenmorph we created to
simulate sketching at free hand". Then a tilingMorph to apply
crystallographic groups. At the next step each designer should
be seeing all the solutions of the other designers and then start
interaction to compose a single solution for the free plan  of
the floor of the ecobuilding.  This step one uses the subgroup
relationships of the crystrallographic groups that smoothly
transforms or adapts  one form into the other.
Before reading about MVC I thought this could be made nicely
through the programmable multiuser virtual reality Kansas.
But this can also be reproduced by the main architectural designer
for simple cases (indeed the need for at least the structural engineer
is always a must).
So my idea is to apply my semiotic knowledge and redesign an
Observer pattern elegantly adapted to fit the case above.
So when the thermal comfort expert changes the free plan, the
architect must be aware of the change and reflect them back into
the free plan concerned with the ecology of the human being
when he lays out the furniture. The philosophy of programming
of the Self language totally based on creation of analogies plus
the unifying paradigm of human-machine interaction is fundamental
for the architectural design.
This interaction is also characterized as hermeneutic or the way
art is.
I also have to be concerned with the autopoietic aspect of my
ecodesign model essentially based on recursive  and reflective
abilities enhancing evolvability from the microworld to the macro
Hope I have conveyed my ideas neatly.Obviously I am not
at all interested in programming in class-based languages.Simply
because the objects in architecture have an arbitrary, individualistic
nature. However they can grow from each other based on analogies.
Like the morphic nature.

Any suggestion from the Selfers is welcome.

Best wishes

> Albertina,
> > Now I have a very specific question and for me it is very important
> > it is answered in a scientifc way!!!
> I think you ended up forgetting your question, for I didn't find it in
> the rest of the text. So I will suppose that you are interested in
> known if Self has an implementation of the Observer Pattern similar to
> Smalltalk-80.
> The answer is: no. Morphic handles this in a less flexible way than
> MVC. Each object sends "changed" to itself whenever its internal state
> is changed and the same object should do something about it. The idea
> in Morphic is that each object should appear only once on the screen
> and so we don't need multiple viewers.
> An exception to this is outliners, which when representing a morph can
> be on the screen at the same time as the morph itself. The morph "view"
> is updated by the "changed" code, but the outliner isn't. Instead, the
> outliner uses the periodic "step" method to poll the object and see if
> anything has changed. This is not efficient, but gets the job done.
> This is why an outliner sometimes takes several seconds to reflect
> changes to an object you have sent a message to.
> Please note that the original creators of MVC are now using Morphic
> exclusively.
> > As fundamental as the Observer appears to be in Smalltalk it is
> > not a language feature (language feature and construct is the same
> > thing?); it is a feature of most Smalltalk libraries.
> Yes: language feature and language construct is the same thing. No:
> Observer is not a fundamental Smalltalk pattern. It is key to MVC, but
> you can have Smalltalks with other graphical systems and not need it at
> all. So it is a good thing that the ANSI standard ignores it.
> -- Jecel
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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