fizzbuzz.rb

def fizz(n)
  n % 3 == 0 ? 'fizz' : ''
end

def buzz(n)
  n % 5 == 0 ? 'buzz' : ''
end

def fizzbuzz(n)
  tmp = fizz(n) + buzz(n)
  tmp == '' ? n : tmp
end

(1..30).each { |n| p (fizzbuzz(n)) }

fizzbuzz1.rb

def fizz(n, negated)
  (n % 3 == 0) ^ negated ? 'fizz' : ''
end

def buzz(n, negated)
  (n % 5 == 0) ^ negated ? 'buzz' : ''
end

def fizzbuzz(n, negated)
  tmp = fizz(n, negated) + buzz(n, negated)
  tmp == '' ? n : tmp
end

puts "=== normal ==="
(0..15).each { |n| puts "fizzbuzz(#{n}, false) => #{fizzbuzz(n, false)}" }

puts ""
puts "=== negated ==="
(0..15).each { |n| puts "fizzbuzz(#{n}, true) => #{fizzbuzz(n, true)}" }

fizzbuzz2.rb

def fizz(n, negated)
  (n % 3 == 0) ^ negated ^ (n < 0) ? 'fizz' : ''
end

def buzz(n, negated)
  (n % 5 == 0) ^ negated ^ (n < 0) ? 'buzz' : ''
end

def fizzbuzz(n, negated)
  tmp = fizz(n, negated) + buzz(n, negated)
  tmp == '' ? n : tmp
end

puts "=== normal ==="
(0..15).each { |n| puts "fizzbuzz(#{n}, false) => #{fizzbuzz(n, false)}" }

puts ""
puts "=== negated ==="
(0..15).each { |n| puts "fizzbuzz(#{n}, true) => #{fizzbuzz(n, true)}" }

puts ""
puts "=== minus ==="
(0..15).each { |n| puts "fizzbuzz(#{-n}, false) => #{fizzbuzz(-n, false)}" }

puts ""
puts "=== minus negated === "
(0..15).each { |n| puts "fizzbuzz(#{-n}, true) => #{fizzbuzz(-n, true)}" }