I was wondering how to access a global function fn
in ruby from a class which also defined a method fn
. I have made a workaround by aliasing the fu
At the top-level a def
adds a private method to Object
.
I can think of three ways to get the top-level function:
(1) Use send
to invoke the private method on Object
itself (only works if the method is not a mutator since Object
will be the receiver)
Object.send(:fn)
(2) Get a Method
instance of the top-level method and bind it to the instance you want to invoke it on:
class Bar
def fn
Object.instance_method(:fn).bind(self).call
end
end
(3) Use super
(assumes no super classes of Bar
below Object
redefine the function)
class Bar
def fn
super
end
end
UPDATE:
Since solution (2) is the preferable one (in my opinion) we can try to improve the syntax by defining a utility method on Object
called super_method
:
class Object
def super_method(base, meth, *args, &block)
if !self.kind_of?(base)
raise ArgumentError, "#{base} is not a superclass of #{self}"
end
base.instance_method(meth).bind(self).call(*args, &block)
end
end
Use like the following:
class Bar
def fn
super_method Object, :fn
end
end
Where the first argument to super_method
must be a valid superclass of Bar
, the second argument the method you want to invoke, and all remaining arguments (if any) are passed along as parameters to the selected method.