Re: branch master updated: licenses: Export license record.

[zimoun]

On Thu, 23 Apr 2020 at 21:57, Ludovic Courtès <address@hidden> wrote:

> address@hidden skribis:
>
> > commit f0779922ff260df2404c90504986aa59553154fb
> > Author: zimoun <address@hidden>
> > AuthorDate: Thu Apr 23 16:09:00 2020 +0200
> >
> >     licenses: Export license record.
> >
> >     * guix/licenses.scm (<license>): Export it.
> >
> >     Signed-off-by: Mathieu Othacehe <address@hidden>
>
> > -  #:export (license? license-name license-uri license-comment
> > +  #:export (license license? license-name license-uri license-comment
>
> I see two issues:
>
>   1. The commit log doesn’t match the change.  :-)

Which part?


>   2. It’s on purpose that the constructor is not exported.  It’s so that
>      genuine license objects have to be defined here.  (Likewise, record
>      type descriptors like <license> are generally kept private to
>      maintain encapsulation.)

How to extend the list by custom licenses without defining them there?


> I’m in favor of reverting.
>
> What’s the use case, Simon?  (Apologies if I missed the discussion!)

I want to be able to have custom licenses for custom packages living
in custom channels.

More or less for example such use case; for reference [1].

--8<---------------cut here---------------start------------->8---
(define-module (my-module)
  #:use-module (guix packages)
  #:use-module (guix licenses)
  #:use-module (gnu packages))

(define mine
  (license "mine"
       "https://my.domain.com";
       "My weird license that no one uses"))

(define-public my-pkg
  (package
   (name "foo")
   (license mine))
--8<---------------cut here---------------end--------------->8---


My point is: license should not be different from the API point of
view than origin or package records; for extension purpose.
Well, the package included in Guix should only be licensed by one of
the licenses in licenses.scm; obviously.

But why does Guix impose this point of view to custom packages living
in custom channels?


I understand the encapsulation point but I miss how to extend the
licenses list without exporting the constructor.


[1] https://lists.gnu.org/archive/html/help-guix/2020-04/msg00119.html


Cheers,
simon