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

to_sym 

        # String.to_sym

(from ruby core)
---
    to_sym()

---

Returns the Symbol corresponding to *str*, creating the symbol if it did
not previously exist. See Symbol#id2name.

    "Koala".intern         #=> :Koala
    s = 'cat'.to_sym       #=> :cat
    s == :cat              #=> true
    s = '@cat'.to_sym      #=> :@cat
    s == :@cat             #=> true

This can also be used to create symbols that cannot be represented using
the `:xxx` notation.

    'cat and dog'.to_sym   #=> :"cat and dog"


(This method is an alias for String#intern.)

Returns the Symbol corresponding to *str*, creating the symbol if it did
not previously exist. See Symbol#id2name.

    "Koala".intern         #=> :Koala
    s = 'cat'.to_sym       #=> :cat
    s == :cat              #=> true
    s = '@cat'.to_sym      #=> :@cat
    s == :@cat             #=> true

This can also be used to create symbols that cannot be represented using
the `:xxx` notation.

    'cat and dog'.to_sym   #=> :"cat and dog"

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.