[Melbourne-pm] CPAN module
Scott Penrose
scottp at dd.com.au
Wed Mar 15 01:48:51 PST 2006
On 15/03/2006, at 20:29, Rick Measham wrote:
> Scott Penrose wrote:
>> CPAN & Debian are virtually identical, as is all Package
>> Management systems.
>
> I'd disagree here, but am happy to be wrong.
>
> With apt you can have many repository sources, they are all
> searched for the highest-version number when you ask to install a
> given package.
You are agreeing with me :-)
> With CPAN.pm you give it a list of repositories, but that's only
> for high-availability. The module gets an up-to-date module list
> from the first repository that is willing to give it. Recently the
> repository I've been using here in .au stopped updating and so I
> had no new sources since December 18th. CPAN.pm gave me a warning,
> but didn't bother checking any other mirror for a more up-to-date
> list.
Yes sort of. But APT is not a package management system, I wrote that
wrong, that is dpkg - APT is a repository management system really -
all about multiple repositories. (this is an oversimplification and
they run together).
This discussion has been confusing because everyone is mixing their
metaphores.
CPAN - is a single repository - like Debian.org - not Debian the
system, not debians package management system DPKG, not the APT
system for getting multiple repositories downloaded etc etc.
CPAN.pm - is a system for accessing that repository - and it is like
the old DPKG download system dselect - which was used before APT - it
was not very flexible.
> When I ask to install a module that list is considered canonical.
> CPAN.pm does not check any other repository for any other version.
> You cannot set up a new CPAN repository with a single module and
> put that at the top of your urllist, and have all other modules
> installed from the second preference.
>
> Many apologies if I'm wrong :)
Sort of. CPAN itself is for accessing CPAN. And CPAN is not a System
like APT, which is designed to have multiple repositories. CPAN IS
the repository. It is like having a repository (in debian anyway)
called "debian-unofficial" - that is the name of the repository. The
name of the CPAN repository is CPAN.
Package management systems are usually broken up into three things.
1) The repository - of which you can have many
2) The collection system (not sure of the right name for this thing)
- of which you can have many
eg: apt is one for Debian which works with others in concurrency
3) The package management/install system - there must be only one of
these.
In Debian these are:
1) (simplified) debian.org, debian-unofficial.org, cdrom, etc
2) apt, dselect, (there used to be heaps others but apt is so good we
just use that now)
3) dpkg
In Perl these are usually:
1) CPAN & Manually installed
2) CPAN (only really works with CPAN, but see previous post for
alternatives) & Manual
3) Perl Modules (it is self managed and can even have multiple
versions installed at once)
But of course this is an over simplification - what about APT &
Debian - they too can install Perl Modules.
So to answer Mathew's original question - he can use APT or GenToo or
RPM or MakeUpYourOwnModule or the CPAN modules I mentioned to manage
his repository.
But... that is not CPAN.
So Rick - yes you are right CPAN is really the repository and it
comes with a free tool to get stuff - but people have extended it to
be both part 1 and part 2 - but what matters is part 3 - and you can
have multiple concurrent paths to part 3.
CPAN - Comprehensive Perl Archive Network - NOT a package management
system - a repository.
Scott
--
* - * http://www.osdc.com.au - Open Source Developers Conference * - *
Scott Penrose
VP in charge of Pancakes
http://linux.dd.com.au/
scottp at dd.com.au
Dismaimer: If you receive this email in error - please eat it
immediately to prevent it from falling into the wrong hands.
Please do not send me Word or PowerPoint attachments.
See http://www.gnu.org/philosophy/no-word-attachments.html
Microsoft is not the answer. It's the question. And the answer is no.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: PGP.sig
Type: application/pgp-signature
Size: 186 bytes
Desc: This is a digitally signed message part
Url : http://mail.pm.org/pipermail/melbourne-pm/attachments/20060315/4a323f72/PGP.bin
More information about the Melbourne-pm
mailing list