From: Brian Candler <b.candler@...>
Date: 2009-12-15T20:35:32+09:00
Subject: Re: meta-programming

Jes炭s Gabriel y Gal叩n wrote:
> irb(main):051:0> C.add_method(:name) {@name}
> => #<Proc:0xb7cb9de8@(irb):51>
> irb(main):052:0> C.add_method(:name=) {|value| @name = value}
> => #<Proc:0xb7cb3bf0@(irb):52>
> irb(main):053:0> c = C.new
> => #<C:0xb7cb16d4>
> irb(main):054:0> c.name=3
> => 3
> irb(main):055:0> c.name
> => 3

Of course, since 'name' is static here, you could just include a module.

It gets more fun when the names of the accessors themselves are dynamic. 
At this point it really does make more sense to use string eval, rather 
than the alternative (instance_variable_get and instance_variable_set).

Have a look at define_method_attribute= in the following:
http://github.com/rails/rails/blob/master/activerecord/lib/active_record/attribute_methods/write.rb

Also see define_read_method in attribute_methods/read.rb, and 
method_missing in base.rb (this defines finder methods dynamically)
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