We need to add role annotations for 7.8

Sven Panne svenpanne at gmail.com
Mon Mar 24 14:25:23 UTC 2014

2014-03-24 15:14 GMT+01:00 Mark Lentczner <mark.lentczner at gmail.com>:
> Speaking from the vantage point of platform.... This pair of comments
> (emphasis mine) have my alarm index on high:
> On Fri, Mar 14, 2014 at 2:36 AM, Johan Tibell <johan.tibell at gmail.com>
> wrote: [...]
>> So, the best thing we came up with is this: Libraries that wish to export
>> abstract data types must do two things:
>> 1. Manage export lists carefully.
>> 2. Use role annotations.
> This is huge order, and one that will produce significant strain on the
> ecosystem. For one, this will set back Haskell Platform months: We have 250k
> lines of Haskell by 30+ authors that will need to be reviewed and updated. [...]

Hmmm, I didn't follow role annotations at all so far, because I
assumed it was of no concern to me as a library author *unless* I use
some shiny new machinery in my library. Did I misunderstand that? How
can I find out if I have to do something? What happens if I don't do
something? What about Haskell systems which are not GHC? Do I have to
#ifdef around those annotations? :-P

I'm a bit clueless, and I'm guess I'm not alone... :-/ If this new
feature really implies that massive amount of library code review, we
should discuss first if it's really worth the trouble. The GHC release
and the HP are already late...


More information about the Libraries mailing list