From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ricardo Wurmus <rekado@elephly.net>
Subject: bug#22437: Fixing package-with-python2
Date: Sun, 07 Feb 2016 10:32:44 +0100
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To: Efraim Flashner <efraim@flashner.co.il>
Cc: guix-devel <guix-devel@gnu.org>, 22437@debbugs.gnu.org


Efraim Flashner <efraim@flashner.co.il> writes:

> On Wed, 03 Feb 2016 09:47:15 +0100
> ludo@gnu.org (Ludovic Courtès) wrote:
>
>> ludo@gnu.org (Ludovic Courtès) skribis:
>> 
>> > An idea I haven’t taken the time to test yet would be to use
>> > ‘properties’:
>> >
>> >   (define python-foobar   ;with Python 3
>> >     (package
>> >       (name "foobar")
>> >       ;; Specify which Python 2 variant to use.
>> >       (properties `((python2-variant . ,(delay python2-foobar))))))
>
> This part I don't get. What's the period for?

The “properties” field holds a regular alist.  Here the alist has one
entry (a pair) with a symbol “python2-variant” as the key, and “,(delay
python2-foobar)” as its value.

The period is needed for the “dotted list” syntax, which is used to
distinguish a pair (or an improper list) from a well-formed list.

~~ Ricardo