Version 11 partitioning: Constraint exclusion vs Partition Pruning

Good afternoon,

I am contemplating implementing partitioning in Postgres v 11.  I am
reading the documentation and came across this statement in the Constraint
Exclusion section:
*Constraint exclusion only works when the query's WHERE clause contains
constants (or externally supplied parameters).   *
Is this true also in Partition pruning?  I don't see a similar statement in
that section.
If we can place variables in the where clause and have partitioning still
work, that would be an awesome enhancement.  I see that Declarative
partitioning was implemented in version 10 and a whole raft of partitioning
enhancements in version 11.  (We are currently at 9.4 and want to upgrade
as well).

-- 
*Mark Steben*
 Database Administrator
@utoRevenue <http://www.autorevenue.com/> | Autobase
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