On Fri, Oct 05, 2001 at 06:22:43PM -0700, Paul Eggert wrote:
> > From: "Gary V. Vaughan" <[EMAIL PROTECTED]>
> > Date: Fri, 5 Oct 2001 22:46:36 +0100
> >
> > libtool needs to store lots of script snippets in shell variables to
> > be passed to eval later. In order for this to work, it must be
> > possible to backslash escape shell meta characters, so that eval's
> > behaviour is predictable.
>
> In this case I don't think it's feasible to require a POSIX shell on
> the part of the installer, as you probably still want to run on bare
> SunOS 4.1.4. So it's a somewhat different case from LINENO, which
> isn't needed for correct operation of "configure".
>
> That being said, have you tried doing something like this as a replacement
> for escaped_something=`echo "$something" | sed 's/\\/\\\\/g'`?
>
> case $something in
> *\\*)
> awk_script='{
> input=$0
> output=""
> while ((i = index(input, "\\")) != 0) {
> output = output substr(input, 1, i) "\\"
> input = substr(input, i + 1)
> }
> print output input
> }'
> escaped_something=`awk "$awk_script" <<EOF
> $something
> EOF
> `
> ;;
> *)
> escaped_something=$something;;
> esac
No, I haven't tried this sort of thing. But I am willing to
experiment on the HEAD branch. Unfortunately, my hacking time is much
reduced for the next month or three so I am barely managing to keep up
with patch submissions.
> This is a bit hard to read, but it is quite portable and you can
> package it up into an Autoconf macro. And in the common case where
> $something contains no backslashes, this solution runs about 50 times
> faster than the echo|sed solution (at least, on my Solaris 8 box).
>
> Maybe something like this should be added to Autoconf. Certainly
> Autoconf is now buggy in more than one place, if "configure" is passed
> operands that contain backslashes.
I think this is certainly worth a try. If it works out, we would then
be in a position to think about reexecing with a shell that supports
functions (cf. my other mail in this thread), and configure scripts
could be a whole lot shorter!
Cheers,
Gary.
--
())_. Gary V. Vaughan gary@(oranda.demon.co.uk|gnu.org)
( '/ Research Scientist http://www.oranda.demon.co.uk ,_())____
/ )= GNU Hacker http://www.gnu.org/software/libtool \' `&
`(_~)_ Tech' Author http://sources.redhat.com/autobook =`---d__/
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