From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2009-12-02T03:52:14+09:00
Subject: Re: Class variables, instance variables, singleton; Ruby v.

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David Masover:

> class Line
>   attr_reader :a, :b
>   def slope
>     (a.x - b.x) / (a.y - b.y)
>   end
> end

> No one has to know that @slope no longer exists.

> Granted, you might have some coders who deliberately break things by
> talking to @slope directly, but if you've defined an accessor, they
> have to be a masochist to want to do it that way. Similarly, because
> it's just one command for you to define them, you really have no
> excuse not to.

Also, if they=E2=80=99re accessing @slope directly, they deserve punishment
=E2=80=93 and I don=E2=80=99t mean =E2=80=98deserve=E2=80=99 solely in the =
bad-for-them sense, but also
in a good-for-them way: it means their code was tailored to work with
version X of your code, and if it relied on such low-level internals,
it=E2=80=99s actually beneficial for them to know outright that your intern=
al
representation changed (and they might want to examine all of the places
in their code that depend on the internal state of your objects).

=E2=80=94 Shot
--=20
Clinical psychology seems designed for people too
smart for religion but not smart enough for science.
                   [Paul Lutus, Asperger=E2=80=99s by Proxy]

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