我发现了这个问题
here.
并且真的很想知道在Rails中实现类似30.seconds.ago的技术解释.
方法链？数字使用情况如下：
http://api.rubyonrails.org/classes/Numeric.html#method-i-seconds
还有什么？
解决方法
Here是秒的执行：
def seconds
ActiveSupport::Duration.new(self,[[:seconds,self]])
end
并且,here是以前的实施：
# Calculates a new Time or Date that is as far in the past # as this Duration represents. def ago(time = ::Time.current) sum(-1,time) end
def sum(sign,time = ::Time.current) #:nodoc:
parts.inject(time) do |t,(type,number)|
if t.acts_like?(:time) || t.acts_like?(:date)
if type == :seconds
t.since(sign * number)
else
t.advance(type => sign * number)
end
else
raise ::ArgumentError,"expected a time or date,got #{time.inspect}"
end
end
end
要完全理解它,您应该按照方法调用并在Rails源代码中查找它们的实现,就像我刚才给您看到的那样.
在Rails代码库中查找方法定义的一种简单方法是在Rails控制台中使用source_location：
> 30.method(:seconds).source_location # => ["/Users/rislam/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/core_ext/numeric/time.rb",19] > 30.seconds.method(:ago).source_location # => ["/Users/rislam/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/duration.rb",108]