module Clamp
  class Parameter

    module Parsing

      protected

      def parse_parameters

        self.class.parameters.each do |parameter|
          begin
            value = parameter.consume(remaining_arguments)
            send("#{parameter.attribute_name}=", value) unless value.nil?
          rescue ArgumentError => e
            signal_usage_error "parameter '#{parameter.name}': #{e.message}"
          end
        end

      end

      def parse_environment_parameters

        self.class.parameters.each do |parameter|
          next if parameter.environment_variable.nil?
          next unless ENV.has_key?(parameter.environment_variable)
          # Set the parameter value if it's environment variable is present
          value = ENV[parameter.environment_variable]
          send("#{parameter.attribute_name}=", value)
        end

      end

    end

  end
end