Ricardo Wurmus <rek...@elephly.net> skribis: > Efraim Flashner <efr...@flashner.co.il> writes: > >> On Wed, 03 Feb 2016 09:47:15 +0100 >> l...@gnu.org (Ludovic Courtès) wrote: >> >>> l...@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.
This is a relic of the old days and probably kind of confusing to newcomers, but since we started making this field an alist, let’s keep it this way. Ludo’.
