Question

I have an ActiveRecord class – lets call it comments – which has an author attribute.

In my code at one point I have passed an instance of comments and the symbol :author to a helper method. I now find myself wanting to access the author attribute and was wondering if there’s a way of doing this with what I have.

I can use comment.read_attribute :author but I can’t use comment.write_attribute :author as it is a private method.

I suspect I’m missing something quite obvious. Any ideas?

Answer 1

You can use instance_eval

irb(main):006:0> class MyClass
irb(main):007:1> attr_accesor :length
irb(main):008:1> end
irb(main):012:0> c = MyClass.new
=> #<MyClass:0x27d6458>
irb(main):016:0> b = 11
=> 11
irb(main):019:0> c.instance_eval( "self.length = #{b}" )
=> 11
irb(main):020:0> c.length
=> 11
irb(main):019:0> c.instance_eval( "self.length" )
=> 11

or

irb(main):021:0> c.send :length
=> 11