# Convenient
require 'sorting/convenience'
people.sort_by { |person| [asc(person.first_name), asc(person.last_name), desc(person.age)] }

# Or without patching Kernel
require 'sorting'
people.sort_by { |person|
  [Sorting.asc(person.first_name), Sorting.asc(person.last_name), Sorting.desc(person.age)]
}

# Care about expensive comparison values which may not always be needed
# assume item.expensive_value takes a lot of time to compute, but since it's the second value,
# it might only be needed in a small number of cases.
require 'sorting/convenience'
items.sort_by { |item|
  [asc(item.cheap_value), asc(:nils_last) { item.expensive_value }]
}

# Care about nil values in your data
require 'sorting/convenience'
people.sort_by { |person|
  [asc(person.first_name, :nils_first), asc(person.first_name, :nils_last)]
}

# Only care about nil values in your data
[5,3,nil,9].sort_by { |x| x || Sorting::Bigger } # Sorting::Smaller is available too