gistfile1.rb

# When we're working with validations in AR, remember that most of them are accepting hashes as arguments.
# For example, we could re-write

validates :email, { :uniqueness => true }

# as

validates(:email, { :uniqueness => true })

# which pretty clearly shows that we have two arguments for the validates method, a symbol and a hash

# Now, about that hash argument... We're currently creating it using the 'rocket' notation:

{ :uniqueness => true }

# The key in the key/value pair is the symbol ':uniqueness', and the value in the key/value pair is the
# Boolean 'true'.
# HOWEVER - we could also create the exact same hash using different notation, like below:

{ uniqueness: true }

# The different notation just says "Hey, Ruby, can you take this first thing ('uniqueness'), turn it into a symbol,
# and then make that symbol the key for this key/value pair? Oh, and could you also be awesome and make that second
# thing ('true') the value for this key/value pair? Thanks!"

# So basically if we write:

{ uniqueness: true }

# Ruby is super nice to us and turns it into:

{ :uniqueness => true }

# However, if you really wanted a string as your key, this alternative way to create a hash would
# totally mess things up! We'd write:

{ "uniqueness": true }

# and Ruby would flip out because it doesn't know what to do! We'd get the error

syntax error, unexpected ':', expecting =>

# So, if you want to use anything other than a symbol for our key, you need to use the rocket notations for hashes!

# Here are a few examples of ways to write hahses and how Ruby would interpret our writing for further clarification:

#   How we write the hash                   How Ruby interprets the hash
    { uniqueness: true }           ==         { :uniqueness => true }
    { "uniqueness": true }         ==         syntax error, unexpected ':', expecting =>
    { "uniqueness" => true }       ==         { "uniqueness" => true }
    { 1 => true }                  ==         { 1 => true }
    { 1: true}                     ==         syntax error, unexpected ':', expecting =>