Variables ...

[Future]

Now i been searching the forums for some basic help on variables and its enoying... I been scanning around the existing scripts and that and i have become confused... I would like if someone could just quickly set my straight.

Okie i looked through the script and it looks quite similar to php (he says)
now what is with the @ and $, whats the difference?

Erhm what i wanted to do for my game was do some custom exp script,
that simply does this:

if Skill_Exp = 1000
then Skill_Level =+ 1
then say Well done you have gained a level.

Can someone quickly help me !! :S
Sorry if i have posted in the wrong forum... :-/

 

[Jared]

local variables begins with a lowercase letter
example: name, _EXP, i
(but I would ever write local variables completly in lowercase lettern)
They work only in the code block, where they are created. Local variables are also used as arguments.
example:

def test
  i = 5 #i is a local variable
  i += 1 #i is now 6
end
test #call the method test
print(i) 
#this i is not the i in the method test, because this are two different code blocks
#so the output would be NIL, because there exist no local variable i in this block

instance variaböes begins with @
example: @Test, @object, @exp
(Here I would ever write in lowercase lettern, too. Also not @Test, but @test)
Instance variables works only in the object where they are created. When the object change his class, the instance variables will be erased in the cache.

class Hero
  def initialize
    @exp = 0
  end
end

Now the variable @exp is IN an object of the class hero.
To get extern access to this variable use the module-method attr_accessor

class Hero
attr_accessor(:exp)
  def initialize
    @exp = 0
  end
end
alex = Hero.new
alex.exp = 500
print(alex.exp)

Class variables beginns with @@. They works for a class and for all objects of the class.
example: @@counter, @@last_id
They are defined in the class, not in a method.

class Hero
  @@counter = 0
   def initialize
     @@counter += 1
   end
   def self.counter?
      p("There are " + @@counter.to_s + " heroes")
end
alex = Hero.new
judy = Hero.new
Jannis = Hero.new
Hero.counter #output: There are 3 heroes

global variables begins with $
example: $game_player, $game_map
They works global, also overall in the script. And every object has access to them.

$test = "Hello"
class A
  def initialize
    $test += " how"
  end
end
class B
  def initialize
    $test += " are"
  end
  def next_word
    $test += " you?"
  end
end
a = A.new
b = B.new
b.next_word
p $test #output: "Hello how are you?"

At least there are constants. They begin with a uppercase lettern.They can be defined everywhere but they can not be changed. When they are defined in a class or module, you get access through modulename::constantname
constants are usefull for class- and modulnames and for every value which you often need but which is ever the same.
example

module Constants
  MY_NAME = 'Jared'
end
p Constants::MY_NAME #output: 'Jared'

For your EXP-Script you should use a instance variable in the $game_actor object.

class Game_Actor
  attr_reader(:skill_exp, :skill_level)
  GAIN_SKILL_LEVEL = 'Well done you have gained a level!'

  def initialize(actor_id) #original script
    super() #original script
    setup(actor_id) #original script
    @skill_exp = 0 #new script
    @skill_level = 0 #new script
  end

  def add_exp(value)
    @skill_exp += value
    if @skill_exp >= 1000 then @skill_level += 1; p(GAIN_SKILL_LEVEL); @skill_exp = 0; end
  end
end

Of course that´s only an example. Instead of the p-method you should work with bitmaps and the draw_text method.

 

[Future]

Thankyou so much i will try and absorb this ^^

Would be quite nice if u can explain what "def initialize" means and some other things, just so i know what you are talking about

 

[Jared]

def initialize is a special method of every object which is called when the object is created.

class Test
  def initialize
    print("This method is called now!")
  end
end
my_object = Test.new  #output: "This method is called now!"

The method new creates a new object and give him the variable (also the adress) my_object. After this the method initialize is called. In initialize methods you can define the start_conditions of an object. Other methods musst be called with object_name.method_name
example:

class Test
  def initialize
    print("This method is called first!")
  end
  def write!
    print("This method musst is called when I wish it.")
  end
end
object = Test.new #output:"This method is called first!"
object.write! #output:"This method musst is called when I wish it."

 

[Future]

Okay ill do some test and then i come back
Thankyou for replying tho ;P

Okay... Another question is how can i call this using the script event?
It would seem you cant simply say "object.write!" in the script event?!

EDIT: Sorry for Double Post

 

[Jared]

When you have access to this event, yes.

Example: The gold-value of your party is an instance variable of the object $game_party. Because $game_party is global, you have overall access to it and because the attr_readergold) method in the Game_Party class give you reading-access to this gold object, you can read the gold value everywhere.

(example in a CallRubyScript)

print($game_party.gold)

But from CallRubyScript you has only access to global variables (and their instance objects, if they are accessible by attr_accessor, attr_writer or attr_reader), local variables IN the Call Ruby Script window, Constants, Classes (and their class-variables) and instance variables in the Interpreter-Class (because CallRubyScript is a method in the Interpreter-Class).

When you create a local object in a CallRubyScript, this object will be erased when CallRubyScript is executed. Is it a instance_variable, the object will be erased when you leave the map. Is it a global variable, the object survived so long you wish.

 

[Future]

Personaly i think you should be promoted ^^ You are realy helpful
Anyways ill try it out :p do u have msn?! i would like to chat to you somemore not just about Scripting

But anyways i dont understand how to run Object.write! im just trying things with the script you have supplied :p

 

[Daniel]

Call object.write! using either:

Test.new.write!

or

object = Test.new
object.write!