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To: gentoo-dev@g.o
From: Mike Frysinger <vapier@g.o>
Subject: Re: lastpipe
Date: Fri, 25 May 2012 20:52:00 -0400
On Friday 25 May 2012 18:33:43 Ciaran McCreesh wrote:
> On Fri, 25 May 2012 15:02:32 -0500 Dan Douglas wrote:
> > If it were made a policy now that ebuilds and eclasses cannot depend
> > upon the subshell (for example, to set temporary positional
> > parameters or isolate temporary variables), then maybe someday in the
> > distant future this could be made the default, and in the meantime,
> > an option for those with new enough shells. Since dependence on the
> > subshell isn't very common, I think this should be feasible, and of
> > course as a workaround all that's required is to wrap any such
> > commands in parentheses.
> 
> We'll be able to turn that on in a controlled way in EAPI 6. Having
> said that, if we're reaching the point where speed of bash code is
> at all relevant, then ebuilds are doing something wrong...

i don't think speed is the main motivator, but rather avoiding behavior that 
bites new people all the time:
	count=0
	printf '%s\n' a b c | \
	while read line ; do
		: $(( count++ ))
	done
	echo $count

w/out lastpipe, that shows 0.  w/lastpipe, that shows 3.
-mike
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Re: lastpipe
-- Dan Douglas
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lastpipe
-- Dan Douglas
Re: lastpipe
-- Ciaran McCreesh
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Updated Jun 29, 2012

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