Re: Org schemas we talked to be non-free, was: [ELPA] New package: repology.el

[Eli Zaretskii]

> From: Ulrich Mueller <ulm@gentoo.org>
> Cc: Jean Louis <bugs@gnu.support>,  ulm@gentoo.org,  rms@gnu.org,
>   dgutov@yandex.ru,  ams@gnu.org,  arthur.miller@live.com,
>   emacs-devel@gnu.org
> Date: Sun, 24 Jan 2021 21:36:54 +0100
> 
> >>>>> On Sun, 24 Jan 2021, Eli Zaretskii wrote:
> 
> >> > Only a special class of derivative works can be distributed freely,
> >> > and it sounds like some of these would fall under "fair use" anyway.
> >> > Certainly this isn't enough to qualify as a free software license?
> >> > 
> >> >    However, this document itself may not be modified in any way,
> >> >             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >> >    including by removing the copyright notice or references to OASIS,
> >> >    except as needed for the purpose of developing any document or
> >> >    deliverable produced by an OASIS Technical Committee (in which case
> >> >    the rules applicable to copyrights, as set forth in the OASIS IPR
> >> >    Policy, must be followed) or as required to translate it into
> >> >    languages other than English.
> >> 
> >> Then it is not free.
> 
> > Forgive me for a possibly naïve question, but why on earth would you
> > want to modify a schema?
> 
> I think the core question isn't if the files can be modified, but if
> their license allows including them with a free software package.

Where does the stuff that you quoted disallow that?

> At least if you apply the usual criteria mechanically, I believe the
> answer would be "no".

I very much hope that we don't apply anything of this kind
mechanically.

> > It's the same as modifying a physical law.  Would you say that E = mc²
> > is "non-free" because it cannot be meaningfully modified at will?
> 
> That's an awful analogy.

Why "awful"?  A physical law describes some part of the reality, and
an XML schema describes a certain kind of documents and data types.

> For example, you can modify (i.e. generalise) the formula to E² =
> p²c² + m²c⁴ for an object with nonzero momentum. :-)

A schema can be similarly "generalized" (a.k.a. "extended") without
changing it: you include the schema in your own and then add your own
data types and conditions.