Re: libguile and readline

[Bruce Stephens <B.Stephens@isode.com>]

Richard Stallman <rms@gnu.org> writes:

> * Changes to the distribution
> 
> ** Readline support is no longer included with Guile by default.
> 
> Based on the different license terms of Guile and Readline, we
> concluded that Guile should not *by default* cause the linking of
> Readline into an application program.  Readline support is now offered
> as a separate module, which is linked into an application only when
> you explicitly specify it.
> 
> Although Guile is GNU software, its distribution terms add a special
> to the usual GNU General Public License (GPL).  Guile's license

there's a word missing here.  "special exemption" or "special
relaxation" or something.

> includes a clause that allows you to link Guile with non-free
> programs.  We add this exception so as not to put Guile at a
> disadvantage vis-a-vis other extensibility packages that support other
> languages.
> 
> In contrast, the GNU Readline library is distributed under the GNU
> General Public License pure and simple.  This means that you may not
> link Readline, even dynamically, into an application unless it is
> distributed under a free software license that is compatible the GPL.

This may be a good way of expressing the intent, but I find it
confusing.  The GNU GPL is explicitly about distribution terms: it
doesn't restrict usage.  So I *am* allowed to take a proprietary
application and link it (statically or dynamically) with a copylefted
library such as Readline---I'm just not allowed to distribute such a
combination.  Similarly, I'm allowed to take a copylefted application
and link with proprietary libraries, but I may not be able to
distribute that (but I may be able to, because of the exceptions for
system libraries).

A programmer who distributes a non-free application which requires
Readline (via Guile or otherwise) is clearly breaking the GNU GPL, but
one who distributes an application linked (or linkable) with Guile is
surely not, whatever extensions a user may wish to add to Guile.

Indeed, surely this flexibility for users to extend applications in
whatever way they want is precisely what Guile is intended to promote?
I agree there's opportunity for misunderstanding with this, so some
new wording is worthwhile.

> Because of this difference in distribution terms, an application
> that can use Guile may not be able to use Readline.  Now users will
> be explicitly offered two independent decisions about the use of
> these two packages.