I personally like yum as well [LWN.net]

I personally like yum as well

Posted Dec 2, 2003 3:22 UTC (Tue) by niemeyer (guest, #17169)
In reply to: I personally like yum by scottt
Parent article: New features in APT-RPM

First, let me position myself. I'm not against yum. I do like the idea of someone working on a completely different implementation, and I'd really like to see yum evolving. Also, I'm a big Python fan, being even one of the contributors of the core language, as you can see in my (wiki|web)log and my projects page.

Now...

"Having to download all that rpm header is sure painful but it lets yum use librpm for dependency handling locally."

APT-RPM meta-information is also based on rpm headers. OTOH, unuseful information in that context is stripped when the "pkglist" (AKA. header list) is created.

"Also note that apt-rpm is implemented in C and it has to make a special effort to "export" its functionality to the lua scripting language"

APT-RPM is implemented in C++, and the important thing about the Lua extension is not the effort I've done to implement it, but how it satisfy users needs.

"The lua code looks quite nice, though a bit too imperative since most people are used to writing filters under the unix shell?"

I don't understand this point. You seem to like the fact that yum is written in Python (as I do).

"While yum is implemented in python utilizing the same python bindings to rpm etc used by the Redhat system management tools."

And APT-RPM is implemented using the C bindings used by every distribution using the RPM API, including the python bindings. Indeed, I belive APT-RPM is the only software today supporting the API of RPM version 3.0.X, 4.0.X, 4.1.X, 4.2.X, and CVS.

"IMHO, programs like yum or apt-get shouldn't be implemented in C."

Agreed. I'd be glad if APT was implemented in Python, but it isn't.

I think the apt-rpm functionality is quite impressive but the difficulty in merging the debian,apt-rpm and Progeny trees is only complicated when the code is in 40000 lines of C instead of 5000 lines of python.

Today, Michael Vogt has sent me a patch of 12kb which makes APT-RPM work in Debian. Also, the APT-RPM port has always been up-to-date with the changes done in the Debian APT, as was written in the article. Progeny is one more in the merging group, and is very welcome. Debian has a slower merging politic, but is merging changes from APT-RPM and Progeny as well.

About the number of lines, I'm sorry, but I don't understand why you belive that this information is relevant, since they have a different set of features and Yum will need a considerable amount of work to get where APT-RPM currently is. Of course, it will still have less lines of code if it ever get into the APT-RPM stage, since it's implemented in Python, but that's not the case right now.

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I personally like yum as well

Posted Dec 2, 2003 4:48 UTC (Tue) by scottt (subscriber, #5028) [Link]

First I would like to thank you personally for your python contributions. I was just using the bz2 module at work yesterday. I didn't recognize your name until I read your projects page.

My comments about the extra effort to support lua and the code size of apt-rpm is really just another way to say I think C/C++ is not the best choice for an implementation language in this case. Though 40000 lines isn't large for a C++ project, complexity still has its cost.The python culture favors C/C++ libraries having python bindings instead of embedding an interpreter in a C/C++ app for a reason.

About the lua code being too "imperative", what I ment was perhaps using a more "functional" style with "iterators" and "map" etc, instead of for-loops and "markinstall". ie. install_devel() in python using an imaginery library:

def devel_packages_to_install():
  def dev_pkgs(pkgs):
    for p in pkgs:
      try:
        yield package(p.name+'-deve')
        yield package(p.name+'-deve-static')
      except:
        pass
  return [ p for p in dev_pkgs(uptodate_packages())
    if not p.is_uptodate() ]
map(lambda p: p.install(),devel_packages_to_install())

As you can see I'm dying for generator comprehensions ;) By the way, does lua have a standard iterator/lazy-list interface?

I personally like yum as well

Posted Dec 2, 2003 5:10 UTC (Tue) by niemeyer (guest, #17169) [Link]

About the "imperativeness", I understand. Lua syntax is indeed a little bit more limited. OTOH, that's expected in a language for embedded environments.

About Lua iterators, yes, the generic 'for' loop allows the underlying function to provide data step-by-step. Lua also implements coroutines, which are the counterpart of Python's generators. For more information, please, check the Lua manual.