From: John Lam <drjflam@...>
Date: 2006-05-04T09:42:32+09:00
Subject: Ruby idiom for attributes / properties

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I'm writing a bunch of auto-marshaling code to let CLR code call back into
Ruby. I just got the simplest possible marshaling scenario working today,
which is letting you bind an Array of ActiveRecord objects to a CLR
DataGridView control. See
http://www.iunknown.com/articles/2006/05/03/activerecord-and-windows-formsf=
or
a longer discussion and a screenshot.

Bottom line is that I can now write:

data_grid.data_source =3D Person.find_by_last_name('Lam')

Now, here's my problem: I'm not all that happy that I'm special casing my
code for ActiveRecord objects. However, since Ruby doesn't have a mechanism
for runtime-discovery of attributes, I'm special casing for ActiveRecord
since it provides an @attributes hashtable with the name-value pairs for al=
l
attributes in the object. This makes it easy for me to generate the CLR
anonymous class + object that implements the marshaling code that retrieves
the attribute data from the Ruby ActiveRecord object (think about this as
marshal by reference).

Do folks have suggestions for implementing a discoverable attribute /
property idiom in Ruby? Perhaps via a mixin module in the standard library?
Or has this been done already and I'm just showing my Ruby newbiness?

Thanks
-John
http://www.iunknown.com

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