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From: Alex Alex on 25 Feb 2010 10:34
Hello all. I have two classes:
class CartItem
attr_reader :product, :quantity

def initialize(product)
@product = product
@quantity = 1
end

def increment_quantity
@quantity += 1
end

def title
@product.title
end

def price
@product.price * @quantity
end
end


class Cart
attr_reader :items

def initialize
@items = []
end

def add_product(product)
current_item = @items.find {|item| item.product == product}
if current_item
current_item.increment_quantity
end
end
end

I don't understand, how class Cart can see method "increment_quantity"
from class CartItem?
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From: Nick Brown on 25 Feb 2010 11:09
Alex: Because Ruby is a dynamically-typed language, it doesn't have to
"see" the method. At runtime, if current_item happens to be an object
with responds to the 'increment_quantity' method, then
current_item.increment_quantity will work fine.

If the object does not respond to that method, it will raise an error.
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From: Eric Christopherson on 25 Feb 2010 18:46
On Thu, Feb 25, 2010 at 10:09 AM, Nick Brown <nick(a)nick-brown.com> wrote:
> Alex: Because Ruby is a dynamically-typed language, it doesn't have to
> "see" the method. At runtime, if current_item happens to be an object
> with responds to the 'increment_quantity' method, then
> current_item.increment_quantity will work fine.
>
> If the object does not respond to that method, it will raise an error.

And methods are public if not specified otherwise.

From: Alex Alex on 26 Feb 2010 01:18
Nick Brown wrote:
> Alex: Because Ruby is a dynamically-typed language, it doesn't have to
> "see" the method. At runtime, if current_item happens to be an object
> with responds to the 'increment_quantity' method, then
> current_item.increment_quantity will work fine.
>
> If the object does not respond to that method, it will raise an error.

Thanks guys
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From: Alex Alex on 26 Feb 2010 01:21
Nick Brown wrote:
> Alex: Because Ruby is a dynamically-typed language, it doesn't have to
> "see" the method. At runtime, if current_item happens to be an object
> with responds to the 'increment_quantity' method, then
> current_item.increment_quantity will work fine.
>
> If the object does not respond to that method, it will raise an error.

And another nuby question:

What class have object "current_item"?
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