module RSpec::Core::MemoizedHelpers::ClassMethods

def let(name, &block)
  # We have to pass the block directly to `define_method` to
  # allow it to use method constructs like `super` and `return`.
  MemoizedHelpers.module_for(self).define_method(name, &block)
  # Apply the memoization. The method has been defined in an ancestor
  # module so we can use `super` here to get the value.
  define_method(name) do
    __memoized.fetch(name) { |k| __memoized[k] = super(&nil) }
  end
end