我想在一些模块中使用实例变量.我目前正在初始化它们,如下所示:
module MyModule
def self.method_a(param)
@var ||= 0
# other logic goes here
end
end
我还可以调用init方法来初始化它们:
def init
@var = 0
end
但这意味着我必须记住要经常打电话给它.
有更好的方法吗?
我想在一些模块中使用实例变量.我目前正在初始化它们,如下所示:
module MyModule
def self.method_a(param)
@var ||= 0
# other logic goes here
end
end
我还可以调用init方法来初始化它们:
def init
@var = 0
end
但这意味着我必须记住要经常打电话给它.
有更好的方法吗?
在模块定义中初始化它们.
module MyModule
# self here is MyModule
@species = "frog"
@color = "red polka-dotted"
@log = []
def self.log(msg)
# self here is still MyModule, so the instance variables are still available
@log << msg
end
def self.show_log
puts @log.map { |m| "A #@color #@species says #{m.inspect}" }
end
end
MyModule.log "I like cheese."
MyModule.log "There's no mop!"
MyModule.show_log #=> A red polka-dotted frog says "I like cheese."
# A red polka-dotted frog says "There's no mop!"
这将在定义模块时设置实例变量.请记住,您可以稍后重新打开该模块以添加更多实例变量和方法定义,
# continued from above...
module MyModule
@verb = "shouts"
def self.show_log
puts @log.map { |m| "A #@color #@species #@verb #{m.inspect}" }
end
end
MyModule.log "What's going on?"
MyModule.show_log #=> A red polka-dotted frog shouts "I like cheese."
# A red polka-dotted frog shouts "There's no mop!"
# A red polka-dotted frog shouts "What's going on?"