Re: [Qemu-devel] Re: [PATCH 01/22] QemuOpts: fix a bug in QemuOpts when setting an option twice

[Gerd Hoffmann]

On 06/08/10 18:04, Anthony Liguori wrote:
> On 06/08/2010 10:37 AM, Gerd Hoffmann wrote:
> > > What'd expect is:
> > >
> > > [net "user"]
> > > guestfwd = <fw1> <fw2> <fw3>..
> > >
> > > I think multiple entry options are probably not a good thing to have.
> >
> > We already have them though (-net switch so QemuOpts added them).
>
> Yeah, but let's ignore that for the moment. If we didn't have historical
> baggage, would we prefer the syntax above or do you think there's value
> in specifying it on separate lines?

guestfwd entries are relatively long, so having them on one line is 
slightly annonying.  I'd tend to have them on separate lines.  But maybe 
it isn't a bad idea to extend the config file syntax to allow being more 
explicit here, like this (borrowed from makefile syntax):

  option := value       assign, overriding any existing value(s)
  option += value       append

Maybe also

  option ?= value       set only in case it isn't set yet.

cheers,
  Gerd