From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pz0-f47.google.com ([209.85.210.47]) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1ShsjJ-0003lf-Dk for openembedded-core@lists.openembedded.org; Fri, 22 Jun 2012 03:32:09 +0200 Received: by dalh21 with SMTP id h21so1571222dal.6 for ; Thu, 21 Jun 2012 18:21:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:message-id:in-reply-to:references:subject:x-mailer :mime-version:content-type; bh=M7shNaCklvokqRjvoG8NW7Cbo7/lGxA748MF+DT8QNQ=; b=ZsIgTBnIpYZ/1CmJ9wyyqsIZqhGJH9EewORTMbPJ3CDGfIHCMFxQG7rocOMf7Y9oWb GGWmnAwVZHIoQl8gL+gxwC1OWeqhhypzZt2Nntuv12fq74/c2o8wrYEY7gQaiXYvuohj p9Wu28+/ufsSdComZw92PElsYmpzSqhGlNS82fL8p1ME/CE5vqighI66R0qUj9W46fC+ J44d2T7bHzWKT0SZzhTMhqfI5vNAkYflOEyh2N6HOEBfF0AJi2PN08SSUSWXHnWZpCB2 ZyG2PBvq00GLH/Qb3wyENxlDEGLNxWr9GK4w9/X3lgS3ycc+JGyZpw7w9JlqvCymr0HB KQMw== Received: by 10.68.132.166 with SMTP id ov6mr4747615pbb.24.1340328081788; Thu, 21 Jun 2012 18:21:21 -0700 (PDT) Received: from [192.168.1.132] (ip68-109-186-98.ph.ph.cox.net. [68.109.186.98]) by mx.google.com with ESMTPS id jz4sm37284688pbc.17.2012.06.21.18.21.17 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 21 Jun 2012 18:21:18 -0700 (PDT) Date: Thu, 21 Jun 2012 18:21:17 -0700 From: Christopher Larson To: Patches and discussions about the oe-core layer Message-ID: <482060616F6643A2B9718B9504DB510B@gmail.com> In-Reply-To: References: <2651001.mzcHSCxQpi@helios> X-Mailer: sparrow 1.6 (build 1081.27) MIME-Version: 1.0 Cc: Paul Eggleton Subject: Re: some simple questions about assignment and appending X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: Patches and discussions about the oe-core layer List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Jun 2012 01:32:09 -0000 Content-Type: multipart/alternative; boundary="4fe3c88d_74b0dc51_7c58" --4fe3c88d_74b0dc51_7c58 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline The only assignment operator that forces immediate expansion is :=. Otherwise expansion always occurs when the value is used. This is inspired by the behavior of GNU Make. See http://www.gnu.org/software/make/manual/html_node/Flavors.html#Flavors for details of how it works there. -- Christopher Larson On Tuesday, June 19, 2012 at 1:49 PM, Robert P. J. Day wrote: > On Tue, 19 Jun 2012, Paul Eggleton wrote: > > > On Tuesday 19 June 2012 12:28:22 Robert P. J. Day wrote: > > > > > finally, what are the evaluation mechanics of the "?=" operator? > > > > ?= is the same as = except that it only sets the value if it is not > > already set at the time the line is parsed. > > > > > just so i don't come across as a total idiot, i did understand that > "?=" is a conditional assignment -- my question was whether it had > immediate evaluation semantics like ":=" or delayed evaluation > semantics like "=", and you appear to have answered that. thanks. > > rday > > -- > > ======================================================================== > Robert P. J. Day Ottawa, Ontario, CANADA > http://crashcourse.ca > > Twitter: http://twitter.com/rpjday > LinkedIn: http://ca.linkedin.com/in/rpjday > ======================================================================== > > _______________________________________________ > Openembedded-core mailing list > Openembedded-core@lists.openembedded.org (mailto:Openembedded-core@lists.openembedded.org) > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core > > --4fe3c88d_74b0dc51_7c58 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
The only assignment operator that forces immediate expansion is :=3D.= Otherwise expansion always occurs when the value is used. This is inspir= ed by the behavior of GNU Make. See http://www.gnu.org/software/make= /manual/html=5Fnode/=46lavors.html=23=46lavors for details of how it work= s there.

-- 
Christopher L= arson

=20

On Tuesday, June 19, 2= 012 at 1:49 PM, Robert P. J. Day wrote:

On Tue, 19 Jun 2012, Paul Egglet= on wrote:

On = Tuesday 19 June 2012 12:28:22 Robert P. J. Day wrote:

finally, what are the evaluation me= chanics of the =22=3F=3D=22 operator=3F

=
=3F=3D is the same as =3D except that it only sets the value if it i= s not
already set at the time the line is parsed.

just so i don't come across as a total i= diot, i did understand that
=22=3F=3D=22 is a conditional assig= nment -- my question was whether it had
immediate evaluation se= mantics like =22:=3D=22 or delayed evaluation
semantics like =22= =3D=22, and you appear to have answered that. thanks.

rday

--

=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Rober= t P. J. Day Ottawa, Ontario, CANADA
=

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D

=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F
=20 =20 =20 =20
=20

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