# File lib/rack/mount/analysis/splitting.rb, line 69
      def process_key(requirements, method, requirement)
        separators = separators(method)
        if requirement.is_a?(Regexp) && separators.any?
          generate_split_keys(requirement, separators).each_with_index do |value, index|
            requirements[Key.new(method, index, Regexp.union(*separators))] = value
          end
        else
          if requirement.is_a?(Regexp)
            expression = Utils.parse_regexp(requirement)

            if expression.is_a?(Regin::Expression) && expression.anchored_to_line?
              expression = Regin::Expression.new(expression.reject { |e| e.is_a?(Regin::Anchor) })
              return requirements[method] = expression.to_s if expression.literal?
            end
          end

          requirements[method] = requirement
        end
      end