Slightly complicated solution to level 5 of RubyWarrior: https://www.bloc.io/ruby-warrior

level5.rb

class Safe
  def next_move_for(player)
    return Attack.new if player.is_under_attack?
    self
  end
  
  def act(warrior)
    return warrior.rest! if warrior.health < 15
    return warrior.attack! if warrior.feel.enemy?
    return warrior.rescue! if warrior.feel.captive?
    warrior.walk!
  end
end  

class Attack
  def initialize
  end
  
  def next_move_for(player)
    return Safe.new unless player.is_under_attack?
    self
  end
  
  def act(warrior)
    return warrior.attack! if warrior.feel.enemy?
    warrior.walk!
  end
end

class Player
  def play_turn(warrior)
    @decision ||= Safe.new
    @health ||= warrior.health
    @warrior = warrior
    
    @decision = @decision.next_move_for(self)
    @decision.act(warrior)
    @health = warrior.health
  end
  
  def is_under_attack?
    @warrior.health < @health
  end  
end
  

level6.rb

class Player
  def play_turn(warrior)
    @direction ||= :backward
    @direction = :forward if warrior.feel(@direction).wall?
    @health ||= warrior.health
    @warrior = warrior
    
    action ||= lambda { warrior.rescue! @direction } if we_find_a_captive
    action ||= lambda { warrior.attack! @direction } if there_is_an_enemy
    action ||= lambda { warrior.walk! :backward } if we_need_to_retreat
    action ||= lambda { warrior.rest! } if we_need_to_rest
    
    action ||= lambda { warrior.walk! @direction }
    action.call
    @health = warrior.health
  end
  
  def we_find_a_captive
    @warrior.feel(@direction).captive?
  end
  
  def there_is_an_enemy
    @warrior.feel(@direction).enemy?
  end
  
  def we_need_to_rest
    @warrior.health < 15 && !we_are_taking_hits
  end
  
  def we_need_to_retreat
    @warrior.health < 6 && we_are_taking_hits
  end
  
  def we_are_taking_hits
    @warrior.health < @health
  end
end
  

level7.rb

class Player
  def play_turn(warrior)
    return warrior.pivot! if warrior.feel.wall? 
    @health ||= warrior.health
    @warrior = warrior
    
    action ||= lambda { warrior.rescue!  } if we_find_a_captive
    action ||= lambda { warrior.attack!  } if there_is_an_enemy
    action ||= lambda { warrior.walk! :backward } if we_need_to_retreat
    action ||= lambda { warrior.rest! } if we_need_to_rest
    
    action ||= lambda { warrior.walk! }
    action.call
    @health = warrior.health
  end
  
  def we_find_a_captive
    @warrior.feel.captive?
  end
  
  def there_is_an_enemy
    @warrior.feel.enemy?
  end
  
  def we_need_to_rest
    @warrior.health < 15 && !we_are_taking_hits
  end
  
  def we_need_to_retreat
    @warrior.health < 6 && we_are_taking_hits
  end
  
  def we_are_taking_hits
    @warrior.health < @health
  end
end
  

level8.rb

class Player
  def play_turn(warrior)
    return warrior.pivot! if warrior.feel.wall? 
    @health ||= warrior.health
    @warrior = warrior
    
    action ||= lambda { warrior.shoot! } if there_is_an_enemy
    action ||= lambda { warrior.rescue!  } if we_find_a_captive
    #action ||= lambda { warrior.attack!  } if there_is_an_enemy
    action ||= lambda { warrior.walk! :backward } if we_need_to_retreat
    action ||= lambda { warrior.rest! } if we_need_to_rest
    
    action ||= lambda { warrior.walk! }
    action.call
    @health = warrior.health
  end
  
  def we_find_a_captive
    @warrior.feel.captive?
  end
  
  def there_is_an_enemy
    occupied_spaces = @warrior.look.select {|x| !x.empty?}
    return false if occupied_spaces.empty?
    return occupied_spaces.first.enemy?
  end
  
  def we_need_to_rest
    @warrior.health < 15 && !we_are_taking_hits
  end
  
  def we_need_to_retreat
    @warrior.health < 6 && we_are_taking_hits
  end
  
  def we_are_taking_hits
    @warrior.health < @health
  end
end
  

level9.rb

class Player
  def play_turn(warrior)
    if @first.nil? 
      @first=false
      return warrior.walk!
    end
    
    return warrior.pivot! if warrior.feel.wall? 
    @health ||= warrior.health
    @warrior = warrior
    
    action ||= lambda { warrior.attack!} if warrior.feel.enemy?
    action ||= lambda { warrior.shoot! } if there_is_an_enemy
    action ||= lambda { warrior.rescue!  } if we_find_a_captive
    action ||= lambda { warrior.walk! :backward } if we_need_to_retreat
    action ||= lambda { warrior.rest! } if we_need_to_rest
    
    action ||= lambda { warrior.walk! }
    action.call
    @health = warrior.health
  end
  
  def we_find_a_captive
    @warrior.feel.captive?
  end
  
  def there_is_an_enemy
    occupied_spaces = @warrior.look.select {|x| !x.empty?}
    return false if occupied_spaces.empty?
    return occupied_spaces.first.enemy?
  end
  
  def we_need_to_rest
    @warrior.health < 15 && !we_are_taking_hits
  end
  
  def we_need_to_retreat
    @warrior.health < 6 && we_are_taking_hits
  end
  
  def we_are_taking_hits
    @warrior.health < @health
  end
end