Re: Install Perl scripts with #!/usr/bin/env perl

[Karim Belabas <Karim.Belabas@math.u-bordeaux.fr>]

* Bill Allombert [2015-01-24 18:14]:
> On Sat, Jan 24, 2015 at 12:59:25PM +0100, Karim Belabas wrote:
> > * Bill Allombert [2015-01-24 12:29]:
> > > On Sat, Jan 24, 2015 at 10:49:43AM +0100, Karim Belabas wrote:
> > > > C) For install, we can either
> > > > 
> > > > * provide
> > > > 
> > > >   Configure --installed-perl=<run-time perl binary>
> > > > 
> > > > with Configure's current $perl as a default [ build-machine = target is
> > > > a sensible default ]. Of course, "/usr/bin/env perl" is (now) a valid value;
> > > 
> > > This is a very awkward name for a  Configure option.
> > > Either we should use
> > > --with-perl=<run-time perl binary>
> > 
> > I don't feel strongly about it :-) To avoid the confusion with the
> > build-time binary ...
> > 
> > --with-runtime-perl ?
> > 
> > > or an environment variable
> > > PERL=<run-time perl binary>
> > 
> > Don't understand that one. Who must set the variable ? 
> > 
> > If the packager, then it's awkward (obscure + must change the variable
> > each time a new target is built, effectively the same as Configure --with-perl)
> 
> It is no more awkward than for CC, CFLAGS and LDFLAGS
> you just do
> env PERL="/usr/bin/env perl" ./Configure ...

That's what I meant by "effectively the same as Configure --with-perl". You'd
have
  env PERL="whatever" Configure
instead of
  Configure --with-runtime-perl="whatever"

Awkward in the sense that CC & friends are completely standardized and
many tools abide by their values. I actually have some of these set on
broken systems (e.g. some OS/X versions, Solaris a long time ago) to
avoid broken default tools or pass necessary flags. I then see 
'env CC=...' as a way of temporarily overriding something that's already
sitting in my environment, or injecting it with expected effect.

Here we'd use the non-standard $PERL variable with a non-obvious
meaning (location of a runtime binary *not* to be used at build time),
what I meant by "obscure". And temporarily inject it, just as a
"convenient" way of giving extra arguments to Configure.

It feels more natural (less awkward) to have a bona-fide argument instead
of messing with env. Though I agree it's effectively the same, let's 
*not* provide both. Unless somebody points me to other packages using $PERL
for this very purpose, that is. :-)

Cheers,

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite de Bordeaux         Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux.fr/~kbelabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux.fr/  [PARI/GP]
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