From: Chad Perrin <code@...>
Date: 2011-09-29T02:15:01+09:00
Subject: Re: Ruby Syntax @keywords ||= [ ]

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On Thu, Sep 29, 2011 at 02:07:35AM +0900, Bhavesh Sharma wrote:
> Sorry if this comes across as a dumb question, but what does the
> following syntax mean in ruby.
>=20
> @keywords ||=3D []
>=20
> I understand that its setting the instance variable as an array but what
> is the logical operator '||' doing in there.

The ||=3D operator is exactly what it looks like: "or equals".  That is,
because every valid chunk of code in Ruby is an expression, you can read
"@keywords ||=3D []" as "give me the keywords variables value, or set it
equal to an empty array (and give me that)".

Thus, if the contents of @keywords evaluate to "true" (that is, it
contains some value other than false or nil), that expression simply
evaluates to the value of @keywords.  Otherwise, the expression assigns
the empty array to @keywords, and evaluates to an empty array.

--=20
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]

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