From: "Ian M. Asaff" <ian.asaff@...>
Date: 2012-04-21T10:20:57+09:00
Subject: Re: What does '||=' mean?

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equivalent to

@ivar = @ivar || value

ruby || short circuits, so if @ivar is nil, then value gets assigned to
@ivar. it's referred to as a "nil guard".

see http://forums.pragprog.com/forums/130/topics/3644

On Fri, Apr 20, 2012 at 9:15 PM, Soichi Ishida <lists@ruby-forum.com> wrote:

> Well, as stated in the subject, what does '||=' mean?
>
> It's from
>
>  def current_cart
>    if session[:cart_id]
>      @current_cart ||= Cart.find(session[:cart_id])  #HERE!!!
>      session[:cart_id] = nil if @current_cart.purchased_at
>    end
>    if session[:cart_id].nil?
>      @current_cart = Cart.create!
>      session[:cart_id] = @current_cart.id
>    end
>    @current_cart
>  end
>
> Is this Rails issue? I thought it's some Ruby grammar thing, because I
> know there is an expression, '|='.
>
> Thanks in advance.
>
>
> soichi
>
> --
> Posted via http://www.ruby-forum.com/.
>
>

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equivalent to=A0<div><br></div><div>@ivar =3D @ivar || value</div><div><br>=
</div><div>ruby || short circuits, so if @ivar is nil, then value gets assi=
gned to @ivar. it&#39;s referred to as a &quot;nil guard&quot;.=A0</div><di=
v><br>

</div><div>see=A0<a href=3D"http://forums.pragprog.com/forums/130/topics/36=
44">http://forums.pragprog.com/forums/130/topics/3644</a><br><br><div class=
=3D"gmail_quote">On Fri, Apr 20, 2012 at 9:15 PM, Soichi Ishida <span dir=
=3D"ltr">&lt;<a href=3D"mailto:lists@ruby-forum.com">lists@ruby-forum.com</=
a>&gt;</span> wrote:<br>

<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">Well, as stated in the subject, what does &#=
39;||=3D&#39; mean?<br>
<br>
It&#39;s from<br>
<br>
 =A0def current_cart<br>
 =A0 =A0if session[:cart_id]<br>
 =A0 =A0 =A0@current_cart ||=3D Cart.find(session[:cart_id]) =A0#HERE!!!<br=
>
 =A0 =A0 =A0session[:cart_id] =3D nil if @current_cart.purchased_at<br>
 =A0 =A0end<br>
 =A0 =A0if session[:cart_id].nil?<br>
 =A0 =A0 =A0@current_cart =3D Cart.create!<br>
 =A0 =A0 =A0session[:cart_id] =3D @<a href=3D"http://current_cart.id" targe=
t=3D"_blank">current_cart.id</a><br>
 =A0 =A0end<br>
 =A0 =A0@current_cart<br>
 =A0end<br>
<br>
Is this Rails issue? I thought it&#39;s some Ruby grammar thing, because I<=
br>
know there is an expression, &#39;|=3D&#39;.<br>
<br>
Thanks in advance.<br>
<span class=3D"HOEnZb"><font color=3D"#888888"><br>
<br>
soichi<br>
<br>
--<br>
Posted via <a href=3D"http://www.ruby-forum.com/" target=3D"_blank">http://=
www.ruby-forum.com/</a>.<br>
<br>
</font></span></blockquote></div><br></div>

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