ruby里的require、load与include

require、load类似java中的import，引入别的文件中定义的类
include用于实现mixin，引入module。
[code]
# Mixins.rb
module D
def initialize(name)
@name =name
end
def to_s
@name
end
end

module Debug
include D
# Methods that act as queries are often
# named with a trailing ?
def who_am_i?
"#{self.class.name} (\##{self.object_id}): #{self.to_s}"
end
end

class Phonograph
# the include statement simply makes a reference to a named module
# If that module is in a separate file, use require to drag the file in
# before using include
include Debug
# ...
end

class EightTrack
include Debug
# ...
end

ph = Phonograph.new("West End Blues")
et = EightTrack.new("Real Pillow")
puts ph.who_am_i?
puts et.who_am_i?
[/code]

require、load 引用的文件需用引号引起来，也可以使用String对象

a='motorcycle'
require a
m = MotorCycle.new('Yamaha', 'red')

A module may contain constants,methods and classes
No instances