'-' an undifined method :S

[Clayton]

ok, I'm doing an assignment in Ruby, and we have to create a Script Generator for B Westerns. Basically I've got an Actor class and a Cowboy class which inherits it. I'm trying to do a little interaction right now, and I came upon this problem:

code:

in 'shoot': undefined method '-' for nil:NilClass (NoMethodError)

and I have no idea why. any help would be greatly appreciated, my code so far:

Ruby:

#the script generator program, yay... #done in Ruby of course. class Actor     attr_reader :name, :emotion, :status     def initialize(name, emotion)         @name = name         @emotion = emotion         @status = "alive"     end     def speak(text)         puts @name + ": " + text     end     #only a cowboy/girl and it's children shall be passed     def be_shot_by(an_actor)         @emotion = "scared shitless"         @status = "dead"         an_actor.shoot(self)         puts "Bang!"         speak("you... shot me.... (Dies)")     end     def be_threatened_by(an_actor)         @emotion = "terrified"         speak("Ok... I don't want any trouble, please don't hurt me!")     end end class Cowboy < Actor     #A cowboy's favorite weapon, the six shooter, has 6 bullets     @six_shooter = 6     def shoot(an_actor)         puts "(" + @name + " shoots at " + an_actor.name + ")" #if @six_shooter > 0         @six_shooter = @six_shooter - 1     end     def be_shot_by(an_actor)         @emotion = "calm cool and collected"         if @six_shooter > 0             self.shoot(an_actor)             speak("Ha ha ha! You think you can shoot at me and get away with it!?")         end     end end actor1 = Actor.new("Bob", "timid") cowboy1 = Cowboy.new("Jesse James", "leader") actor1.be_shot_by(cowboy1)

[wtd]

Simple. In the shoot method, the @six_shooter instance variable is nil.

Yet, you would surely assert that you did in fact assign a value to it.

Consider that in Ruby, classes are objects.

[Cervantes]

wtd speaks truth. There's a difference in what happens when you define a class in Ruby and when you define a class in Turing. You've coded in the Turing style, assuming that the code inside the class is run every time a new object is created. But that's not the Ruby way.

Just read the beginning of the Dynamic Classes tutorial.

Now, ask yourself, where does the @six_shooter instance variable live?

[Clayton]

Okay, so @six_shooter lives inside the Object class, but where does that leave me? I'm still confused

I read the tutorial, but I'm still unclear how that applies here.

[ericfourfour]

Couldn't you just slap an initialize method into Cowboy, call super and initialize six_shooter?

[Clayton]

that's actually exactly what I did, it was just talked about in the IRC channel, much more convenient