Public qualified import

[lukaszcz]

It should be possible to write

import A as B public

with the effect of all identifiers in A re-exported qualified with B.

One could also want to use/hide specific identifiers to be re-exported qualified:

import A as B using {a; b} hiding {c; d} public

Perhaps the as syntax should just be merged into open as one of the options?

import A open as B using {a; b} hiding {c; d} public

The idea is that we're moving the identifiers from A into a different scope, either the current one (no as) or into the scope specified with as.