From: "David A. Black" <dblack@...>
Date: 2008-08-14T03:52:45+09:00
Subject: Re: Ruby 1.9: What to Expect by Sam Ruby @ OSCON 2008 Slide Deck Adapted S6/S9 (Single-Web Page) Version

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Hi --

On Thu, 14 Aug 2008, I=C3=B1aki Baz Castillo wrote:

> El Martes, 12 de Agosto de 2008, David A. Black escribi=C3=B3:
>> If you want to use a non-parameter inside a block and have it not
>> clobber an outside variable, you can declare it as a local variable by
>> putting it after a semi-colon in the parameter list:
>>
>> =C2=A0 =C2=A0{|x,y,z;a| a =3D 1 } =C2=A0 =C2=A0# a is not bound to any b=
lock args but is
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0# local to the block
>
>
> Could I use that to avoid the problem if I do this:
>
>  Thread.new(request) { |request| ... }
>
> This is a big problem since the "request" into the block points to the re=
quest
> outside, so each thread share it (dangerous). This is why I use:
>
>  Thread.new(request) { |req| ... }
>
> Could I use this?
>  Thread.new(request) { |;request| ... }

No, because you then have no block parameter to which to bind the
thread object. Variables listed after the semi-colon are available as
local variables in the block, but do not participate in the argument
bindings.


David

--=20
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  *  Advancing With Rails    August 18-21    Edison, NJ
  * Co-taught by D.A. Black and Erik Kastner
See http://www.rubypal.com for details and updates!
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