Hi,

I'm new to the Ruby and Ruby on Rails world. I've read some guides, but i've some trouble with the following syntax. I think that the usage of :condition syntax is used in Ruby to define a class attribute with some kind of accessor, like:

class Sample
  attr_accessor :condition
end

that implicitly declares the getter and setter for the "condition" property. While i was looking at some Rails sample code, i found the following examples that i don't fully understand.

For example:

@post = Post.find(params[:id])

Why it's accessing the id attribute with this syntax, instead of:

@post = Post.find(params[id])

Or, for example:

@posts = Post.find(:all) 

Is :all a constant here? If not, what does this code really means? If yes, why the following is not used:

@posts = Post.find(ALL)

Thanks