From: Bill Atkins <batkins57@...>
Date: 2005-05-08T05:46:00+09:00
Subject: Re: Prove me Wrong! Re: RCR 303: nil should accept missing methods

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 object =3D get_some_object # get_some_object returns nil
object.perform_action_of_great_importance # action never gets performed - n=
o=20
error

On 5/5/05, John Carter <john.carter@tait.co.nz> wrote:
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> On Fri, 6 May 2005, Alexey Verkhovsky wrote:
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> > John Carter wrote:
> >
> >> A very simple and generic way of improving the reliability of Ruby
> >> programs is to implement the NullObject pattern by allowing nil to
> >> accept all and every method instead of throwing a NoMethodError.
> >
> > I, for one, would rather see it throwing an error as it is now. Dead=20
> programs
> > don't tell lies.
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> I would suggest next 5 times you have a nil class throws
> NoMethodError crash, just add this at the head of your program...
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> class NilClass
> def method_missing( sym, *args)
> nil
> end
> end
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> And see what happens.
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> If, your program then works correctly, then I am right.
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> If, your still program thows an exception or reports an error, but perhap=
s
> a slightly different point, then I am still right, namely this change
> doesn't hide bugs.
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> If the program silent proceeds to do the wrong thing, then I am wrong.
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> I ask members of this list to actually try this experiment the next coupl=
e
> of times they hit a nil throws NoMethodError and send the results to me.
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> I will summarize to the list.
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> If I prove wrong, I will gladly retract my RCR and apologise.
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> John Carter Phone : (64)(3) 358 6639
> Tait Electronics Fax : (64)(3) 359 4632
> PO Box 1645 Christchurch Email : john.carter@tait.co.nz
> New Zealand
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> This rock is covered by a very very thin layer of life. (Think 6000km
> of rock followed by a meter or so of biomass.)
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>=20


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Bill Atkins

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