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Re: automake/44: conditional redefinitions (Was: Re: Automake 1.6.3issue)
- From: Alexandre Duret-Lutz <duret_g at lrde dot epita dot fr>
- To: Akim Demaille <akim at epita dot fr>
- Cc: tromey at redhat dot com, automake at gnu dot org, automake-gnats at sources dot redhat dot com
- Date: Thu, 31 Oct 2002 18:13:18 +0100
- Subject: Re: automake/44: conditional redefinitions (Was: Re: Automake 1.6.3issue)
- References: <3D73D239.A9D5A86D@pacbell.net><mv4n0qvtqfw.fsf@nostromo.lrde.epita.fr><3D7A3BD5.B649DE1B@pacbell.net><mv4vg5fpmcm.fsf@nostromo.lrde.epita.fr><3D7D435B.7B2E3F3D@pacbell.net><mv4znuq87wi.fsf@nostromo.lrde.epita.fr><3D7DFD73.F88E9E37@pacbell.net><mv4admp7w5j.fsf@nostromo.lrde.epita.fr><3D7E1CC4.4A35883F@pacbell.net><2002-09-10-18-57-50+31582+duret_g@lrde.epita.fr><877kht6s1x.fsf@fleche.redhat.com><2002-10-11-23-04-05+19905+duret_g@lrde.epita.fr><mv465vmvipb.fsf@nostromo.lrde.epita.fr>
>>> "Akim" == Akim Demaille <akim@epita.fr> writes:
[...]
Akim> Nevertheless, I agree a means to install defaults would
Akim> be most welcome.
Akim> I suggest introducing
Akim> foo ?= bar
Akim> Which is always valid, but with a clear semantics.
Assuming your semantic is that of BSD make: "assign unless set" [*],
I can see how this help in
if COND1
foo = mumble
endif
if COND2
foo = blurgle
endif
foo ?= else
But I fail to see how you'd use this to override a default
value whose definition has been included from elsewhere.
(Unless inclusions of fragments defining default variables are
done at the end of Makefile.am -- but this raises a few other
issues.)
[...]
[*] IIRC someone once sent a patch against Automake to introduce
`?=' as "assign and allow future redefinitions".
--
Alexandre Duret-Lutz