class Regexp::Expression::Conditional::Condition

def initialize_copy(orig) 

def initialize_copy(orig)
  self.referenced_expression = orig.referenced_expression.dup
  super
end

def reference

Returns a String if reference is by name, Integer if by number.
Name or number of the referenced capturing group that determines state. 
def reference
  ref = text.tr("'<>()", "")
  ref =~ /\D/ ? ref : Integer(ref)
end