def gen_method_parameters direction, parameters, file
      return if parameters.empty?
      file.print "#{direction.inspect} => ["
      first = true
      parameters.each do |p|
        if first
          first = false
        else
          file.print ", "
        end
        # [ <name>, <type>, <out>? ]
        file.print "#{p.name.inspect}, #{p.type.to_sym.inspect}"
      end
      file.print "]"
      return true
    end
def gen_method_parameters direction, parameters, file
      return if parameters.empty?
      file.print "#{direction.inspect} => ["
      first = true
      parameters.each do |p|
        if first
          first = false
        else
          file.print ", "
        end
        # [ <name>, <type>, <out>? ]
        file.print "#{p.name.inspect}, #{p.type.to_sym.inspect}"
      end
      file.print "]"
      return true
    end
generate method parameter information
 return nil if no parameters