This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.

sort_by! 

        # Array.sort_by!

(from ruby core)
---
    array.sort_by! {|element| ... } -> self
    array.sort_by! -> new_enumerator

---

Sorts the elements of `self` in place, using an ordering determined by
the block; returns self.

Calls the block with each successive element; sorts elements based on
the values returned from the block.

For duplicates returned by the block, the ordering is indeterminate, and
may be unstable.

This example sorts strings based on their sizes:
    a = ['aaaa', 'bbb', 'cc', 'd']
    a.sort_by! {|element| element.size }
    a # => ["d", "cc", "bbb", "aaaa"]

Returns a new Enumerator if no block given:

    a = ['aaaa', 'bbb', 'cc', 'd']
    a.sort_by! # => #<Enumerator: ["aaaa", "bbb", "cc", "d"]:sort_by!>

This is MURDOC! A Ruby documentation browser inspired by Smalltalk-80. It allows you to learn about Ruby by browsing through its class hierarchies, and see any of its methods.