Add Finding The Source of Ruby Methods as a ruby til.

README.md

@@ -50,6 +50,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Are They All True?](ruby/are-they-all-true.md)
 - [Create an Array of Stringed Numbers](ruby/create-an-array-of-stringed-numbers.md)
 - [Destructuring Arrays In Blocks](ruby/destructuring-arrays-in-blocks.md)
+- [Finding The Source of Ruby Methods](ruby/finding-the-source-of-ruby-methods.md)
 - [Limit Split](ruby/limit-split.md)
 - [Parallel Bundle Install](ruby/parallel-bundle-install.md)
 - [Summing Collections](ruby/summing-collections.md)

ruby/finding-the-source-of-ruby-methods.md

@@ -0,0 +1,29 @@
+# Finding The Source of Ruby Methods
+
+Ruby's [`Method`](http://ruby-doc.org/core-1.9.3/Method.html) class
+includes a feature that can help you quickly find the location of
+source code files where a particular method is defined. The method is aptly
+named [`source_location`](http://ruby-doc.org/core-1.9.3/Method.html#method-i-source_location).
+
+When debugging a project that is using the
+[Treat](https://github.com/louismullie/treat) gem, you can take a source dive
+by first finding the relevant source files. For instance, if you want to look
+into the word creation functionality, you might go through an exploratory
+process like the following:
+
+```ruby
+> require 'Treat'
+=> true
+> Treat::Entities::Word.build('stuff')
+=> Word (70331843958460)  --- "stuff"  ---  {}   --- []
+> Treat::Entities::Word.method(:build)
+=> #<Method: Class(Treat::Entities::Entity::Buildable)#build>
+> Treat::Entities::Word.method(:build).source_location
+=> ["/Users/jbranchaud/.gem/ruby/2.1.4/gems/treat-2.1.0/lib/treat/entities/entity/buildable.rb", 29]
+```
+
+You can now take a closer look at the implementation of the `build` method.
+
+The main caveat to this process is that it can only find source locations
+for methods defined in ruby land. Calling `source_location` on any method
+defined in C code will result in `nil`.