Re: guile-json, SRIFs and licenses

[John Cowan]

On Sat, Nov 9, 2019 at 8:29 AM Mark H Weaver <address@hidden> wrote:


> You're mistaken.  A GPLed library can be used by any program covered by
> a *GPL-compatible* license.
>

At the cost of making the resulting work as a whole under the GPL.


> Those are major historical examples, but the same thing happens quite
> frequently and unremarked in smaller examples, whenever a boss would
> reflexively tell an employee that a program they wrote should be kept
> proprietary, but is compelled to make it free software because it
> depends on a copylefted library (such a Guile-JSON).
>

Well, I suppose that happens; certainly it has happened in the past, as
your examples show.  However, all the bosses I have worked for in the last
few decades (and I've made my living for forty years as most programmers
do, by writing proprietary software), simply say "No GPLed components,
ever.  If he has to pay for me or another to write the components
ourselves, he'd much rather do that than the alternative.

My present employer takes a slightly more enlightened view.  Employes are
free to contribute to existing open-source projects on whatever terms.
Like most, we use GPLed programs in proprietary shell scripts, which the
FSF allows, and I wrote and GPLed a wrapper around an existing GPLv3
library to transform it into a server (our code opens a raw TCP connection,
writes data, reads the results back).  That repo is not yet publicly
available, but it will be made so when the release that uses it is
distributed to our customers.

> Whether or not a GPLed JSON library requires the Scheme implementation
> > to be itself GPL depends on the implementation, but certainly a
> > stand-alone *application* that uses it would have to be.
>
> Again, you are mistaken.  Check your facts, please.  See
> <https://www.gnu.org/licenses/gpl-faq.html#WhatIsCompatible>.
>

That page defines GPL-compatibility thus:  "[If] the other license and the
GNU GPL are compatible, you can combine code released under the other
license with code released under the GNU GPL in one larger program.  All
GNU GPL versions permit such combinations privately; they also permit
distribution of such combinations provided the combination is released
under the same GNU GPL version."

Thus if the JSON library is combined into the Scheme implementation as part
of it, and that implementation is released, it must be released under the
GPL.  If a stand-alone application (as opposed to a mere script that
invokes the implementation) written in Scheme makes use of a GPLed library,
it too (if publicly distributed) must be GPLed.  That's what I said

As for clang, Apple funded it for commercial reasons, but there were
efforts among BSD developers to write their own C compiler for years before
that, though they came to nothing.



John Cowan          http://vrici.lojban.org/~cowan        address@hidden
Ambassador Trentino: I've said enough. I'm a man of few words.
Rufus T. Firefly: I'm a man of one word: scram!    --Duck Soup