Re: [gentoo-dev] Antwort: Re: [gentoo-dev] YaST will be GPL [Virus checked]

[Stuart Herbert]

On Saturday 20 March 2004 12:06, John Nilsson wrote:
> I never ment that Gentoo developers would do some non standard things to
> the packages. If the standard is not good enough to convince upstream
> developers to change, it is not good enough, period.

It'll never happen.  XML isn't something that everyone accepts is always a 
good thing.  In many languages, handling XML content programmatically is a 
RightRoyalPain(tm).  And we currently lack adequate XML-aware diff and grep 
tools - two things essential to making this work.

> The generated file would be a xml-file. This xml-file would be the
> package "normal" config file.

So how would the config tool know how to generate the XML file?  A schema is 
nowhere near enough.

> The whole point is that the Schema to validate the xml-file would be
> developed by the upstream package developers.

It would be interesting to find out what percentage of XML dialects have 
either DTDs or schemas to allow validation.  Maybe it's just the circles I 
move in, but DTDs or schemas are things that I rarely see used.

It would also be interesting to see how many languages have support for 
validating XML input through DTDs and schemas.

> This schema would also contain the documentation for the configuration
> file. From this Schema a man-page could be generated. Thus config tools
> and man-pages would have the same source of information.

A bit like Perl and their POD files?

> It might be true that I narrowly think XML. I have recently studied it
> for a solution to some work related projects.
> However I think it is a good solution in any case. One could pick any
> syntax imaginable, xml however has the edge of being ready for use
> today.

XML is a reasonable choice for marking up data such as configuration files.  
Personally, I prefer to use it when you're feeding structured data from one 
system to another - because of the ability to validate the input.  I'd rather 
use a relational database technology than XML in static files on disk, 
because it's much more searchable and shareable.  But that's just me.

> > Which developers?  Gentoo developers, or the upstream developers?
>
> Upstream. Gentoo is a meta distribution as you say.  I would call it "a
> proof of concept hack to demonstrate portage" if honest =)
> Don't get me wrong I run Gentoo as my only OS on all my home machines, I
> love it.
> However in another world I would have the portage tree only contain
> forks of the packages and then heavily develop the whole system for
> consistency. One can dream, right?

That's the power of Gentoo.  It could be used to create a whole new 
distribution based on the public Gentoo code.

How many packages are there in the Gentoo tree?  Over six thousand.  Let's say 
you could convert each one in an average of one man day's effort.  I think 
that's optimistic, but it keeps it simple.  Now, a man year is around 200 
days of effort, allowing for weekends, holidays, illness, and overheads.  So 
that's 30 man years of effort to convert what we have today.

If you had RedHat's money, maybe it could be done.  But Gentoo people are 
volunteers.  On average, volunteers on activities outside normal work and 
family commitments manage a man month's worth of effort over 12 months of 
elapsed time.  So you're really looking at 360 years to get it done by 
volunteers.

First you said ...

> > > their Schema must validate against. This uber Schema is formulated in a
> > > way such that a configuration editor, adhering to the standard, can
> > > edit any applications configuration in a secure and user friendly way
> > > without "plugins" or modification.

... and then you said ...

> I'm not talking about a configuration editor.

Sorry, you've confused me there.  I really did think you were talking about a 
configuration editor.

> > I'm describing a
> "protocol" that a configuration editor can implement. The value would be
> that all data required to create a valid configuration file would come
> with the file not with the editor.

How are you going to get the authors of 6,000+ packages to agree to follow a 
single XML schema?

> I can imagine someone engineer a clever XSLT technique to solve some
> Gentoo specific problems without actually touching the packages...

There's no such thing as clever XSLT - just XSLT that becomes an absolute 
nightmare to maintain.

> As stated earlier this system depends on upstream developers to throw
> out their current system and implement this. Thus it has to be GOOD
> ENOUGH.

Easier said than done.  Of course, code speaks louder than words ...  

I can't think of a way in which you could prevent duplication of validation 
logic except one - the validation logic would have to be written in some form 
of scripting language such as JavaScript, and be part of the XML schema 
itself.  XML Schema itself is insufficient, and the moment your shared 
library of code starts needing callbacks (think of the getopt function as an 
example of what I mean) then you end up with duplicated logic.

> All opinions are important, I don't want to wast my time on a system no
> one would use =), how ever i could investigate the matter further and
> deeper if it seems promising.

It's not that I don't think no-one would use it.  The aim of sorting out the 
archane way that UNIX does its config files is an honourable one.  Microsoft 
clearly sees an XML-everywhere strategy as something it can use in the war it 
thinks it has to fight against systems such as Gentoo.  Maybe one day it 
really will give Microsoft a competitive edge (in IP protected ways) that 
will cause us real problems - who knows?

I'm just not convinced you understand the problem domain sufficiently - no, in 
any real depth - at this time, and that you don't understand the barriers to 
adoption.

> Now this isn't Gentoo specific, but it is a system worth considering in
> further "System configuration gui" research.
>
> -John

I think it would help if you had a clearly defined problem to direct your 
research at, and a wide background study of how things are done today and the 
myriad of reasons why.

Best regards,
Stu
-- 
Stuart Herbert                                              stuart@g.o
Gentoo Developer                                       http://www.gentoo.org/
Missed the php|cruise?             http://dev.gentoo.org/~stuart/cruise-2004/

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