From: Florian Gilcher <flo@...>
Date: 2008-05-17T09:24:39+09:00
Subject: Re: Not quite getting it.

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On May 17, 2008, at 1:02 AM, ara.t.howard wrote:

> On May 16, 2008, at 12:45 PM, Roger Alsing wrote:
>
>> Ok ok, as I said, I get type promotion.
>> But what if you assign a "Giraffe" to a property called "Orders" ,  
>> isnt
>> that just as bad or even worse than overflowing a number?
>
>
>
> then you will need a tall box.

Pragmatic Programming ;).

Roger, just because variables are not typed doesn't mean that you can't
check for Types. Actually, Rubys type-system is quite strong, it doesn't
allow casts. You can very easily build objekt properties that check for
type or a certain set of methods. Something like:

class Test
    attr_accessor :order

    def order=(order)
      if order.kind_of?(Giraffe)
        raise Exception.new("We package nearly everything, but  
Giraffes????")
      end
    end
end

So Ruby does typing, but on a different level. It assumes that all  
objects are sane and
then gives you the possiblity to check all the information that the  
object propagates and
use that for reasoning. See it as a service-based approach. Wouldn't  
be the first time
a service does not do what the name implies ;).

The numbers problem: Conceptually, there is also no such thing as an  
"overflowing number",
in Ruby because Ruby abstracts high enough that you as a Programmer do  
not have to to
care about those technical implications. This is a completely  
different ballpark ;).

Regards,
Florian Gilcher
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