Re: dependency mess: i'd like boolean operators
On Fri, Feb 09, 2001 at 12:06:14PM +0100, Domenico Andreoli wrote:
> > Depends: curl (= 7.4.2-2) | curl (>= 7.5-1),
> > libcurl0-ssl (= 7.4.2-2) | curl (>= 7.5-1),
> > curl (= 7.4.2-2) | libcurl1-ssl (>= 7.5-1),
> > libcurl0-ssl (= 7.4.2-2) | libcurl1-ssl (>= 7.5-1)
> >
> this is really interesting, so let me understand more:
>
> 1) the first clause can be simplified as you said below, ok.
>
> 2&3) the second... should be "|" read as XOR (exclusive or)?
> there is no meaning in the order of the operands of "|", right?
> if what i said is correct then second and third cluses are ok.
>
> 4) the fourth clause has sense only if "|" has a XOR meaning.
No, | is the usual alternatives syntax for Depends lines, it's
basically an OR. I derived it this way:
(p & q) | (r & s)
is
((p & q) | r) & ((p & q) | s)
is
(p | r) & (q | r) & (p | s) & (q | s)
It's three applications of the distribution rule for & and |.
The end result looks complicated but has the same meaning as the
original, and it can be expressed in dpkg's Depends syntax.
Richard Braakman
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