> Alle marted 29 maggio 2007, Gian Holland ha scritto:
> > Hi I have a beginner question

> > What does the => operator do?

> > here is the example code from the book

> > class Product < ActiveRecord::Base
> >   has_many :orders, :through *=>* :line_items
> >   #...

> => is not an operator, its simply the syntax used to create hashes:

> h = {:a => 1, :b=>2}

> creates an hash with keys :a and :b, corresponding to values 1 and 2
> respectively. When you need to pass an hash as the last argument of a method,
> ruby allows you to omit the braces, so your call to has many means:

> has_many( :orders, {:through => :line_items} )

> In other words, you're passing two arguments to the method has_many: the first
> is the Symbol :orders; the second is a Hash with one key (:through) and one
> value (:line_items)

> Stefano