class AttrTest
  attr_reader :a
  attr_writer :b
  attr :c
  attr :d, true
  attr_accessor :e
end
o = AttrTest.new
%w(a b c d e).each do |x|
  puts x
  puts ' ' + o.respond_to?(x).to_s
  puts ' ' + o.respond_to?(x + '=').to_s
end
__END__
a
 true
 false
b
 false
 true
c
 true
 false
d
 true
 true
e
 true
 true