From: Eric Hodel <drbrain@...7.net>
Date: 2004-04-07T19:01:46-07:00
Subject: Re: Preferred Instance Variable Access Method

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Jean-Hugues ROBERT (jean_hugues_robert@yahoo.com) wrote:

> Hi,
>=20
> At 05:34 08/04/2004 +0900, you wrote:
> What's the preferred way of accessing a class's instance variables?
>=20
> I tend to use @var instead of self.var (I guess var() would work, and
> var too).
>=20
> I see two advantages:
>   1) Faster (I never benchmarked however)
>   2) Lines starting with @ are like methods with ! at the end =3D>
>         Draw the attention to probable side effect on obj's state.

    3) Avoids setting local variables when you wanted to call a writer.

> I do agree that typos can be an issue. There is warning however,
> with ruby -w (that sometimes warns for some valid constructions
> of mine, I guess defined? could help me avoid that).
>=20
> Refering to a recent thread, I may add that self.var seems slightly
> Python-ish.

Without self., ruby may create a local variable rather than call the
writer method when assigning:

class Foo
  attr_accessor :bar

  def initialize
    @bar =3D "#bar=3D not called yet"
  end

  def meth
    bar =3D "#bar=3D called"
    puts self.bar
  end
end

Foo.new.meth # =3D> #bar=3D not called yet

> I would personally prefer .var but languages with configurable style/
> syntax are rare these days (missing C's #define).

--=20
Eric Hodel - drbrain@segment7.net - http://segment7.net
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