Ruby naming convention / double underscore / useful stuff

Question

I know there is __FILE__, __LINE__, and __send__.

From the Delegator class there are __getobj__ and __setobj__.

Is there any other useful "strange" double underscore goodness present in the Ruby standard library?

Answer 1

This is a complete list for Ruby 2.1:

• __callee__ (Kernel)
• __dir__ (Kernel)
• __method__ (Kernel)
• __id__ (BasicObject)
• __send__ (BasicObject)
• __ENCODING__ (keyword)
• __LINE__ (keyword)
• __FILE__ (keyword)

From delegate:

• __getobj__ (Delegator)
• __setobj__ (Delegator)
• __getobj__ (SimpleDelegator)
• __setobj__ (SimpleDelegator)

From drb:

• __drbref
• __drburi

From irb:

• __evaluate__
• __exit__

From tk:

• All the methods start with a double underscore

Answer 2

There's also the encoding keyword: __ENCODING__:

puts __ENCODING__ # => UTF-8