Executing a mixin method at the end of a class definition
I have a Mix-in that reflects on the receiver class to generate some code. This means that I need to execute 开发者_如何学运维the class method at the end of the class definition, like in this trivially dumbed down example:
module PrintMethods
module ClassMethods
def print_methods
puts instance_methods
end
end
def self.included(receiver)
receiver.extend ClassMethods
end
end
class Tester
include PrintMethods
def method_that_needs_to_print
end
print_methods
end
I'd like to have the mixin do this for me automatically, but I can't come up with a way. My first thought was to add receiver.print_methods
to self.included
in the mixin, but that won't work because the method that I want it to reflect on has not been declared yet. I could call include PrintMethods
at the end of the class, but that feels like bad form.
Are there any tricks to make this happen so I don't need to call print_methods
at the end of the class definition?
First of all, there's no end of class definition. Remember that in Ruby you can reopen the Tester class method after you have 'initialized' it, so the interpreter can't know where the class 'ends'.
The solution I can come up with is to make the class via some helper method, like
module PrintMethods
module ClassMethods
def print_methods
puts instance_methods
end
end
def self.included(receiver)
receiver.extend ClassMethods
end
end
class Object
def create_class_and_print(&block)
klass = Class.new(&block)
klass.send :include, PrintMethods
klass.print_methods
klass
end
end
Tester = create_class_and_print do
def method_that_needs_to_print
end
end
But certainly having to define classes this way makes my eyes hurt.
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