Date: Fri, 16 May 2003 15:30:01 +0300 From: Ruslan Ermilov <ru@freebsd.org> To: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Re: make: variable expansion in .for/.endfor Message-ID: <20030516123001.GD2047@sunbay.com> In-Reply-To: <20030429130143.GK13541@freepuppy.bellavista.cz> References: <20030425184400.GS13541@freepuppy.bellavista.cz> <20030426115336.GF761@straylight.oblivion.bg> <20030427124812.GU13541@freepuppy.bellavista.cz> <20030429103404.GA680@straylight.oblivion.bg> <20030429130143.GK13541@freepuppy.bellavista.cz>
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On Tue, Apr 29, 2003 at 03:01:43PM +0200, Roman Neuhauser wrote:
> # roam@ringlet.net / 2003-04-29 13:34:04 +0300:
> > On Sun, Apr 27, 2003 at 02:48:12PM +0200, Roman Neuhauser wrote:
> > > # roam@ringlet.net / 2003-04-26 14:53:36 +0300:
> > > > On Fri, Apr 25, 2003 at 08:44:00PM +0200, Roman Neuhauser wrote:
> > > > > Try the following makefile: it works if called with -DONE, but does not
> > > > > if called with -DTWO. Should I treat it as a bug and file a PR?
> > > > >
> > > > > LIST= foo bar baz
> > > > >
> > > > > .if defined(ONE)
> > > > > . for v in ${LIST}
> > > > > . if !defined(WITHOUT_${v:U})
> > > > > WITH_${v:U}=yes
> > > > > . endif
> > > > > . endfor
> > > > > .endif
> > > > >
> > > > > .if defined(TWO)
> > > > > . for v in ${LIST}
> > > > > V=${v:U}
> > > > > . if !defined(WITHOUT_${V})
> > > > > WITH_${V}=yes
> > > > > . endif
> > > > > . endfor
> > > > > .endif
> > > > >
> > > > > a:
> > > > > @echo \$${WITH_FOO}: ${WITH_FOO}
> > > > > @echo \$${WITH_BAR}: ${WITH_BAR}
> > > > > @echo \$${WITH_BAZ}: ${WITH_BAZ}
> > > > >
> > > > > .PHONY: a
> > > >
> > > > I think this is a known bug, and it seems to even be documented
> > > > in the BUGS section of -STABLE's make(1) manual page.
> > >
> > > I don't think this is covered. Can you point out the relevant text?
> >
> > Looking at:
> > $FreeBSD: src/usr.bin/make/make.1,v 1.29.2.15 2002/12/17 19:01:18 seanc Exp $
> >
> > The rendered version reads, right at the end of the BUGS section:
> >
> > For loops are expanded before tests, so a fragment such as:
> >
> > .for TMACHINE in ${SHARED_ARCHS}
> > .if ${TMACHINE} = ${MACHINE}
> > ...
> > .endif
> > .endfor
> > won't work, and should be rewritten the other way around.
> >
> > This particular part of the manual page seems to have been there
> > for the past three years, since Tim Vanderhoek's merge from OpenBSD
> > in rev. 1.23.
> >
> > At least, I think that this is similar (actually, nearly identical) to
> > your Makefile fragment.
>
> both fragments are "nearly identical", and the first one works. it's
> the assignment (V=${v:U}) that breaks. so, where's the similarity
> (or identity), given that the snippet from the make man page is
> unrelated to assignments?
>
> again, the first version (wrapped in ifdef ONE) works just fine.
>
Yes, BUGS section talks about a different problem, is that
.for loops are unrolled before parsing, so if loop variable
"v" has the value "X", the
.if ${v} == "foo"
becomes
.if X == "foo"
and now recall the (documented) limitation that "An expression
may also be an arithmetic or string comparison, with the left-hand
side being a variable expansion."
FWIW, the code snippet above works perfectly under 5.x make(1).
I recall this problem was fixed (perhaps, it was even me, not
sure). Sorry, but I don't have enough time to invest into
backporting the bugfix into RELENG_4, the latter is becoming
less priority for me as 5.x evolves.
If you'll be able to extract it from HEAD (there is a huge
backlog of non-backported fixes for make(1) there), I will
happily commit it for you.
$ uname -r
5.1-BETA
$ make -DONE
${WITH_FOO}: yes
${WITH_BAR}: yes
${WITH_BAZ}: yes
$ make -DTWO
${WITH_FOO}: yes
${WITH_BAR}: yes
${WITH_BAZ}: yes
Cheers,
--
Ruslan Ermilov Sysadmin and DBA,
ru@sunbay.com Sunbay Software AG,
ru@FreeBSD.org FreeBSD committer,
+380.652.512.251 Simferopol, Ukraine
http://www.FreeBSD.org The Power To Serve
http://www.oracle.com Enabling The Information Age
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