From: Eric Hodel <drbrain@...7.net>
Date: 2004-07-03T03:58:21+09:00
Subject: Re: How to detect if variable has been defined yet?

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David A. Black (dblack@wobblini.net) wrote:

> Hi --
>=20
> On Sat, 3 Jul 2004, gabriele renzi wrote:
>=20
> > il Fri, 02 Jul 2004 17:40:40 GMT, Randy Lawrence <jm@zzzzzzzzzzzz.com>
> > ha scritto::
> >=20
> >=20
> > defined? may be useful. Anyway, writing:
> >=20
> > if variable
> >  variable+=3D1
> > else
> >  variable=3D0
> > end
> >=20
> > should do just fine
> >=20
>=20
> Have you tried it? :-)
>=20
> $ ruby
> if variable; variable +=3D 1; else variable =3D 0; end
> ^D
> -:1: undefined local variable or method `variable' for
> main:Object (NameError)
>=20
> I think you'd have to use defined?, or conditionally initialize the
> variable:
>=20
>   x ||=3D 0
>   x +=3D 1
>=20
> (Note that you can't condense that into (x ||=3D 0) +=3D 1, though you
> could do: x =3D (x ||=3D 0) + 1 )

Use conditional assignment over defined?.

defined? is a sign of code smell.  Variables should be explicitly
initialized before use.

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