From: Christopher Larson <kergoth@gmail.com>
To: Patches and discussions about the oe-core layer
<openembedded-core@lists.openembedded.org>
Cc: Paul Eggleton <paul.eggleton@linux.intel.com>
Subject: Re: some simple questions about assignment and appending
Date: Thu, 21 Jun 2012 18:21:17 -0700 [thread overview]
Message-ID: <482060616F6643A2B9718B9504DB510B@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1206191647570.3325@oneiric>
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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
> ========================================================================
>
> _______________________________________________
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>
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prev parent reply other threads:[~2012-06-22 1:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-19 16:28 some simple questions about assignment and appending Robert P. J. Day
2012-06-19 17:32 ` Paul Eggleton
2012-06-19 20:49 ` Robert P. J. Day
2012-06-22 1:21 ` Christopher Larson [this message]
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