songs_2.rb

class Song
  attr_reader :name, :artist, :duration

  def initialize(name, artist, duration)
    @name = name
    @artist = artist
    @duration = duration
  end

  def play
    puts "Playing '#{name}' by #{artist} (#{duration} mins)..."
  end

  def each_filename
    basename = "#{name}-#{artist}".gsub(" ", "-").downcase
    extensions = [".mp3", ".wav", ".aac"]
    extensions.each { |ext| yield basename + ext }
  end
end

song1 = Song.new("Okie From Muskogee", "Merle", 5)
song2 = Song.new("Ramblin' Man", "Hank", 7)
song3 = Song.new("Good Hearted Woman", "Waylon", 6)


class Playlist
 include Enumerable

  def initialize(name)
    @name = name
    @songs = []
  end

  def add_song(song)
    @songs << song
  end

  def each
    @songs.each { |song| yield song }
  end

  def play_songs
    @songs.each { |s| s.play  }
  end

  def each_tagline
    @songs.each { |song| yield "#{song.name} - #{song.artist}" }
  end

  def each_by_artist(artist)
    select { |song| song.artist == artist }.each { |song| yield song }
  end

end

playlist = Playlist.new("Country/Western, Y'all!")
playlist.add_song(song1)
playlist.add_song(song2)
playlist.add_song(song3)

# playlist.each { |song| song.play }.play_songs

# playlist.play_songs

# okie_songs = playlist.select { |song| song.name =~ /Okie/ }
# p okie_songs.class

playlist.each_tagline { |tagline| puts tagline }

playlist.each_by_artist("Waylon") { |song| song.play }