python `if __name__ == '__main__'` 等价于 Ruby
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`if __name__ == '__main__'` equivalent in Ruby
提问by Imagist
I am new to Ruby. I'm looking to import functions from a module that contains a tool I want to continue using separately. In Python I would simply do this:
我是 Ruby 的新手。我希望从包含我想继续单独使用的工具的模块导入函数。在 Python 中，我会简单地这样做：
def a():
...
def b():
...
if __name__ == '__main__':
a()
b()
This allows me to run the program or import it as a module to use a()and/or b()separately. What's the equivalent paradigm in Ruby?
这允许我运行程序或将其作为模块导入a()和/或b()单独使用。Ruby 中的等效范例是什么？
回答by Matchu
From the Ruby I've seen out in the wild (granted, not a ton), this is not a standard Ruby design pattern. Modules and scripts are supposed to stay separate, so I wouldn't be surprised if there isn't really a good, clean way of doing this.
从我在野外看到的 Ruby（当然，不是很多）来看，这不是标准的 Ruby 设计模式。模块和脚本应该保持分开，所以如果没有真正好的、干净的方法来做到这一点，我不会感到惊讶。
EDIT:Found it.
编辑：找到了。
if __FILE__ == if caller.length == 0
# do stuff
end
foo()
bar()
end
But it's definitely not common.
但这绝对不常见。
回答by uKolka
If stack trace is empty, we can start executing to the right and left. I don't know if that's used conventionally or unconventionally since I'm into Ruby for about a week.
如果堆栈跟踪为空，我们可以开始向右和向左执行。我不知道这是常规使用还是非常规使用，因为我使用 Ruby 大约一个星期。
#!/usr/bin/ruby
if caller.length == 0
puts "Main script"
end
puts "Test"
Proof of concept:
概念证明：
file: test.rb
文件：test.rb
#!/usr/bin/ruby -I .
require 'test.rb'
puts "Shmest"
file: shmest.rb
文件：shmest.rb
$ ./shmest.rb
Test
Shmest
$ ./test.rb
Main script
Test
Usage:
用法：
if $PROGRAM_NAME == __FILE__
foo()
bar()
end
