Add DList to base

[Ivan Lazar Miljenovic]

On 5 June 2017 at 17:58, Dr.Koster <drkoster at qq.com> wrote:
> Currently GHC already defined DList for internal use in serveral places.
> This data type is a nature choice when you need CPS your append, which is a
> common need. I think base should provide it.

It depends if GHC defines DList for use with base or not; if it's
something that's required to use base that _may_ be a semi-valid use
case.

In general though, as annoying as it is to have to add yet another
dependency, build, reload ghci, etc. I prefer to have base to be
smaller and packages split up and the dlist package serves admirably.
If nothing else, it can iterate faster if a new function needs to be
added.

Call this a weak +0.1(only because of GHC defining it).

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
http://IvanMiljenovic.wordpress.com