De Morgan's laws (in Ruby)

de_morgans_laws.rb

puts "<< De Morgan's laws >>\n\n"

PAIRS = [
  [false, true],
  [true, false],
  [true,  true],
  [false, false]
]

puts "\"NOT (A AND B)\" is the same as \"(NOT A) OR (NOT B)\""
puts "\nYep!" if PAIRS.all? do |a, b|
  puts <<-MSG
  Example: (!#{a} || !#{b}) == !(#{a} && #{b})
    Ruby:
      Bad:  if !#{a} || !#{b}
      Good: unless #{a} && #{b}
  MSG

  (!a || !b) == !(a && b)
end

puts "\n\"NOT (A OR B)\" is the same as \"(NOT A) AND (NOT B)\"."
puts "\nYep!" if PAIRS.all? do |a, b|
  puts <<-MSG
  Example: !(#{a} || #{b}) == (!#{a} && !#{b})"
    Ruby:
      Bad:  if !#{a} && !#{b}
      Good: unless #{a} || #{b}
  MSG

  !(a || b) == (!a && !b)
end

The world could be a better place. https://en.wikipedia.org/wiki/De_Morgan%27s_laws

#  Example: !(false || true) == (!false && !true)"
#    Ruby:
#      Bad:  if !false && !true
#      Good: unless false || true
#  Example: !(true || false) == (!true && !false)"
#    Ruby:
#      Bad:  if !true && !false
#      Good: unless true || false
#  Example: !(true || true) == (!true && !true)"
#    Ruby:
#      Bad:  if !true && !true
#      Good: unless true || true
#  Example: !(false || false) == (!false && !false)"
#    Ruby:
#      Bad:  if !false && !false
#      Good: unless false || false
#
# Yep!