attr_reader and attr_accessor

[PhotonWeapon]

What do they do, exactly? And how can they help you in script-making? And can anybody give an example of each? I saw the Condtional Branch: Items where somebody used attr_reader to allow a conditional branch of having a certain quantity of an item with one line of script, without using an in-game variable to do so, and I thought that was kinda neat.

 

[OceanBlueYoshi]

well attr_reader is just like a variable. Go to http://www.rmxponline.com and click "rgss" and look at the lessons, they tell you what they are andwhat they do

 

[Ceroscuro]

attr_accessor means that variables in that class preceded by the @ symbol can be accessed by other classes. i.e. if you have the variable @chicken in $game_map, you can see change the value of that variable is by using $game_map.chicken.

attr_reader does the same thing except it's like a "read-only" variable. You can't change it, just see the value of it.

 

[Daniel]

And also their is attr_writer, so let's say you put "attr_writer: something" in $game_system. Then you could write to it using "$game_system.something += 1", but you could not read it by using "var = $game_system.something".

attr_accessor, attr_reader, and attr_writer just create access methods.

attr_reader creates this method:

def var
  return @var
end

attr_writer creates this method:

def var=(val)
  @var = val
end

attr_accessor creates both.

 

[PhotonWeapon]

So, normally it is better to use attr_accessor?

 

[Ceroscuro]

You could pretty much use accessor for everything. There's no real disadvantage that I can think of, other than that you could edit a variable that you don't want to edit... but if you don't want that to happen you could just use attr_accessor and just not edit it. :P

 

[PhotonWeapon]

All righty, then! Thanks everybody!:D

 

[Exsharaen]

Oh, thanks for that! I once guessed that attr_reader will read and attr_accessor will write (so I used both whenever I need to access and change value of an attribute), but now I see that attr_accessor does both read and write.