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RE: verbing properties again




 ----------
From:  Michael Moore[SMTP:mike@mail.datasys.net]
Sent:  Friday, July 26, 1996 8:50 AM
To:  Adams, Charles
Cc:  MOO-Cows
Subject:  Re: verbing properties again


Adams, Charles wrote:
>
> I'll never support this ill-founded idea of invisibly "verbing"   
property
> access. When I say foo.bar, I want to see the property "bar" on object
> "foo", and not what someone decides I *should* be seeing instead.  Are   
we
> going to have to design a builtin to mean "I really want the property,   
no I
> really mean it, no, I don't want to go through channels, just connect   
me to
> the property."

What is being talked about here is the concept of encapsulation.   
 Basically,
the idea is, "What goes on behind the scenes in this object is none of   
your
business.  You leave the implementation of it up to me, and I'll provide   
you
a nice standard interface."  The idea of it is that an object manages its
own data, and provides public methods for access to that data.  By
'encapsulating' the data thusly in the object, the object maintains   
ultimate
control of what gets put in the actual property values.  With this kind   
of
control, it becomes much easier to add things like user-defined data   
types
to MOO.  It also provides a much easier way to simulate   
multiple-ownership
of objects, properties, and verbs.

Suppose, for instance, this "verbing properties" is used.  You could then
put a wrapper around properties whose names end with '_msg'.  For the   
most
part, these properties should contain a false value or a string.   
 Sometimes
players get creative and put lists of strings in the properties, then   
until
they correct it they see {list} where they should see that message.  The
wrapper installed could either reject any list values for assignment to   
the
property (raise E_TYPE), or convert lists into single strings.

It is a part of OOP that college hammered into my head...and I'm glad   
they
did.


Agree with that... I'm using a kind wrapper around some
properties to let it choice a the French or English version
of a string depending a language property set on the player
variable. But I continue to find that good encapsulation
can be done with -r property and put some access-controlling
verb around.

Sometime verb have to rely on the consistencies of their
properties. Change in the behavior of one of the ancestors
property-verb can make it return a list in place of a
string... and make all their children OOF (out of function if
you prefered ... ).

Maybe some scoping value like in C++ (see private, protected
and public) can be made to look if only the objects, their
children or everyone can access directly to some properties
of the object but I would put it first in some security
meaning like for -x verb but for wiz or caller_perm(). This
will help to "securise" the server and having all this
security check done in server can, *I think*, reduce the
lag considerably...

That just another 2 pennies in this begin-to-be-long-but-still-
interesting thread.


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contradiction is not that free software are among the best,
   it's that   
commercial software aren't the best of   
them.
===============================================================
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en Ninoles aka the Baggus Mage aka Baffouille
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finger me for my PGP Public   
Key  | Not knowing where you go
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lead you to
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End...
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Can  
 be reach too on Ninoles.Fabien@ic.gc.ca until   
23/08/96
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