Types for Data.Sequence pattern synonyms

[Henning Thielemann]

On Wed, 20 Apr 2016, David Feuer wrote:

> As discussed, I plan to add pattern synonyms Empty, :<|, and :|> to
> make working with sequences more convenient. The remaining question is
> what types they should have. From the Data.Sequence standpoint, the
> best thing would be to make them work *only* for Seq, so that the Seq
> type will be inferred from their use. However, modules using multiple
> sequence types might benefit from more flexibility, via ad hoc
> classes.

I prefer that Data.Sequence exports functions with the Seq type and that 
generalized functions are exported by a different module that is intended 
for generalization. The specific and general infix operators could have 
the same symbol and the user could choose via the module import which one 
to use.