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Re: RFR: more FC4 Requests



Panu Matilainen wrote:

On Sat, 2004-11-20 at 21:23 -0500, Jeff Johnson wrote:


Panu Matilainen wrote:



On Sat, 2004-11-20 at 19:36 -0500, Jeff Johnson wrote:



Sure, people love and use it (for example the Lua-interface is a killer
feature which yum currently lacks) but it's starting to seem like a dead
end to me.



So how should lua be made available to yum?

Current implementation of lua in rpm is through %{lua: ...} macro constructs,
grotesque mainly because of the necessity to preserver a "stable" and constant
rpm-python interface. E.g. there is no way to simply expand a macro, one has to
go through the baggage of hdr.sprintf() where rpmExpand() to invoke lua happens
as side effect. That's obscure enough to pass for "stable", sigh.





I'm not talking about making Lua available to yum, I'm talking about the
mechanism which is *the* killer feature of apt-rpm, not the language
itself. I'd take python over lua any day, it's just that Lua is easier
and smaller to embed compared to python. In yum's case Lua doesn't make
any sense, it's just a matter of allowing "external" python scripts to
affect yum's functionality at certain predefined points. That's what
apt's lua-interface is all about, and I know something like that is
being planned for yum (IIRC under the name "xtriggers" or somesuch)



I'm not talking about lua either. I'm talking about how an existing embedded and scriptable
language (which happens to not be called Forth ;-) in rpmlib might be made available
to applications like yum that use rpmlib in order to incorporate what you call a killer feature, fine
grained hooking within an installer state machine.




Easy enough to rip several layers off the above, what stops is no need to do so yet.

Hum a few notes about what you'ld like to see lua used for in yum, please. I think
lua has definite and positive benefits for rpm packaging, becuase for the first time
rpmlib can run scripts without the baggage of scriptlet dependencies. Lots of dependencies
would (will imho) simply melt away if lua rather than shell were used for the 20 or so
common operations performed by package scriptlets.



Again, Lua has zero to do with this, it's all about adding similar
customization possiblity to yum that's available in apt-rpm currently.



Yup, lua has zero to do with this discussion becuase lua is not called "python" just like rpm is
not called "apt" or "yum".


73 de Jeff



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