Question

How can I find out what class(es) a method is defined in, in Ruby?

For example lets say that I wanted to know what classes implement the to_s method. How would I do that using the ri command?

Answer 1

~$ ri

Enter the method name you want to look up.
You can use tab to autocomplete.
Enter a blank line to exit.

>> to_s

= .to_s

(from gem actionpack-3.1.0.rc6)
=== Implementation from ActionDispatch::RemoteIp::RemoteIpGetter
------------------------------------------------------------------------------
  to_s()

------------------------------------------------------------------------------


(from gem actionpack-3.1.0.rc6)
=== Implementation from ActionView::FileSystemResolver
------------------------------------------------------------------------------
  to_s()

------------------------------------------------------------------------------


(from gem actionpack-3.1.0.rc6)
=== Implementation from ActionView::FixtureResolver
------------------------------------------------------------------------------
  to_s()