From: John Feminella <johnf@...>
Date: 2011-04-04T12:08:39+09:00
Subject: Re: pipe question

An expression like "foo || bar" works like this: First, evaluate the
boolean value of `foo`. If it is boolean-true, then the value of this
expression is `foo`. If not, then the value of this expression is
`bar`.

This expression says, assign the current value of @first_name back
into @first_name. Alternatively, if this is the first time you're
trying to assign it, it'll be nil, so use an empty string instead.

It's equivalent to writing:

    @first_name ||= ''

~ jf
--
John Feminella
Principal Consultant, BitsBuilder
LI: http://www.linkedin.com/in/johnxf
SO: http://stackoverflow.com/users/75170/



On Sun, Apr 3, 2011 at 22:58, wolf volpi <wolf_volpi@yahoo.com> wrote:
> What does the pipe in this example do?
>
>  @first_name = @first_name || ''
>
> According to the text book that this example came from, the code ensures
> that an instance variable is not nil.  If @first_ name is nil, @first_
> name is set to the empty string.
>
> Thank you.
>
> --
> Posted via http://www.ruby-forum.com/.
>
>