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Re: New package dependency field format



On Thu, Sep 04, 2003 at 08:17:28PM +0200, Josip Rodin wrote:
> On Thu, Sep 04, 2003 at 06:13:08PM +0100, Andrew Suffield wrote:
> > > > > > ! is probably needed.
> > > > > 
> > > > > What for, exactly? I can think of
> > > > > 
> > > > > Depends: foo (!= 1.34-2)
> > > > > 
> > > > > but that sounds more like eye candy than really necessary...
> > > > 
> > > > Depends: foo | ! bar
> > > > 
> > > > That can be read as "If bar is installed, then foo must also be
> > > > installed".
> > > 
> > > That still sounds redundant, and can be currently expressed with
> > > 
> > > Depends: foo, foo | bar
> > 
> > No, that requires either foo or bar be installed.
> 
> Which is what "If bar is installed, then foo must also be installed" meant
> if you apply it only to the part after the pipe, as the present parser
> does... I didn't realize that you meant the whole expression means that.
> 
> I guess it shows something about my vgrep, but also about the readability
> of such a thing.

It would make sense if you'd studied formal logic >:)

Conventionally, this is "A implies B", or A -> B. One of the
fundamental equivalences is then A -> B === B | !A

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
 : :' :  http://www.debian.org/ |
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