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PODynamically added accessor assignment doesn't work when invoking block via instance_eval in Ruby
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copied!<p>I have a class to which I add attribute accessors dynamically at runtime. This class forms part a DSL, whereby blocks get passed to configuration methods and invoked using instance_eval. This makes it possible in the DSL to remove references to 'self' when referencing methods of the class.</p> <p>However, I've discovered that I can reference the attributes to retrieve their values, but am unable to assign them, unless explicity referencing self, as the following code sample illustrates.</p> <pre><code>class Bar def add_dynamic_attribute_to_class(name) Bar.add_dynamic_attribute(name) end def invoke_block(&block) instance_eval &block end def self.add_dynamic_attribute(name) attr_accessor name end end b = Bar.new b.add_dynamic_attribute_to_class 'dyn_attr' b.dyn_attr = 'Hello World!' # dyn_attr behaves like a local variable in this case b.invoke_block do dyn_attr = 'Goodbye!' end # unchanged! puts "#{b.dyn_attr} but should be 'Goodbye!'" # works if explicitly reference self b.invoke_block do self.dyn_attr = 'Goodbye!' end # changed... puts "#{b.dyn_attr} = 'Goodbye!" # using send works b.invoke_block do send 'dyn_attr=', 'Hello Again' end # changed... puts "#{b.dyn_attr} = 'Hello Again!" # explain this... local variable or instance method? b.invoke_block do puts "Retrieving... '#{dyn_attr}'" # doesn't fail... but no effect dyn_attr = 'Cheers' end # unchanged puts "#{b.dyn_attr} should be 'Cheers'" </code></pre> <p>Can anyone explain why this isn't behaving as expected?</p>

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