Date: Thu, 10 Aug 2006 10:34:24 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: ports@freebsd.org, Stanislav Sedov <ssedov@mbsd.msk.ru> Subject: Re: make(1) is broken? Message-ID: <200608101034.24589.jhb@freebsd.org> In-Reply-To: <20060810160836.40eb4128@localhost> References: <20060810160836.40eb4128@localhost>
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On Thursday 10 August 2006 06:08, Stanislav Sedov wrote:
> Hi!
>
> I have a strange problem linked with make(1)
>
> Consider the following Makefile:
> ---------------------------------------------------------------
> COMPS=aa ab ac
> AA=aa
>
> VAR1=${COMPS:Maa}
> VAR2=${COMPS:M${AA}}
>
> .for COMP in ${AA}
> VAR3=${COMPS:M${COMP}}
> .endfor
> ---------------------------------------------------------------
>
> Now, running make(1) gives:
> % make -V VAR1
> aa
> % make -V VAR2
> }
> % make -V VAR3
> aa
>
> Results for VAR2 seems quite strange for me. It looks like
> ${COMP}!=${AA}
>
> So, the question: is make(1) broken, or it's my misunderstanding?
>
> Any help greatly appreciated. Thanks!
I think it's your misunderstanding, when you do .for, make expands
$COMP to generate more lines that it then later evaluates, so with the
.for expanded you get:
COMPS=
AA=
VAR1=${COMPS:Maa}
VAR2=${COMPS:M${AA}}
VAR3=${COMPS:Maa}
Then when make evaluates VAR2, it doesn't expand ${AA} but tries to
match that substring ('${AA}') in COMPS. Actually, though, it's less
obvious than that, as since it isn't looking to do variable expansion
in an M modifier, it ends the $COMPS expansion when it sees the first },
so what you end up with is this:
VAR2='${COMPS:M${AA}'}
That is, it tries to match the substring '${AA' in ${COMPS} and then
appends a '}' character to that, which gives the '}' result you saw.
--
John Baldwin
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