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Mailing List Message of <rpm-devel>

Re: Generalizing EVR comparison precedence, preliminaries

From: Jeff Johnson <n3npq@mac.com>
Date: Fri 09 Jan 2009 - 00:03:26 CET
Message-id: <423F40BE-1AD8-4765-B259-A26D80C4140F@mac.com>

On Jan 8, 2009, at 3:24 PM, Ralf S. Engelschall wrote:

> On Tue, Jan 06, 2009, Michael Jennings wrote:
>> [...]
>> So a standalone number is just a release?  Shouldn't that be a
>> version?  (i.e., _3__ for case 6)
> I've just implemented what Jeff told me.
> I wondered myself about this special case, too...
>> And isn't there an ambiguity with E:V vs. V:D?  What about V-R:D? or
>> just :D?
> V:D was not part of Jeff's list, hence no ambiguite existed ;-)

Ask Per Oyvind re Distepoch:. There is no ambiguity if (as currently)
there are almost no occurences of Distepoch:. Only "E:V" occurs atm.

The resolution is likely partly to add [0-9]+ as a pattern for E, which
also is more precisely compatible with the pre-existing EVR parser,  
and or
to invent a different separator rather than ':' D.

But at least the flaws are being seen at the design stages, not after
a patch has been checked-in and deployed and released, where the
only possible resolution is to pretend that what just happened in RPM
was what was intended. An accident like that with  
is indeed the root of years of suspicion between LSB <-> RPM.

So finding flaws sooner is called "progress" in my RPM scrapbook.

> Jeff, can you be more specific what cases you really want to support?

I could be more specific if I knew specifics.

What I'm seeking is a generalization out of traditional E:V-R  
dependencies through
pattern matching and parameterization and templating within RPM.

So I hijacked Per Oyvind's Distepoch: and stirred in a bit of your
dead-on methodology and PCRE expertise, and RPM versions (perhaps) now  
have sufficient
generality that a LSB specification for "package" "versions" can be  
so that indeed, the decision of a "package" "upgrade" is decidable for  
LSB "packages".

LSB details at
Alas, still no publically visible statement-of-work from LSB. Oh  
well ...

Basically I am making "stuff" up as fast I can. I assure you, I'm not
a parser guy, I'm the last hacker in the world you want attempting
a Ragel parser based rewrite of rpmbuild using *RE's instead of  

But a rpmbuild rewrite seems to be my current RPM goal because YAMLspec!
is the only roadmap item @rpm5.org I'm hearing consensus about.

Plus I needed an excuse to learn PCRE syntax ...

I'm quite pleased with the results so far ;-)

73 de Jeff

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Received on Fri Jan 9 00:04:02 2009
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