module system/namespaces: separate with/use, allow local "use"

[Johannes Waldmann]

With the module system, we should make a distinction between declaring

(1) that we want to use a module
(2) how to bring the module's names into scope

E. g. in Ada, there is "with" and "use", and "use" can be local,
see also http://www.dcs.gla.ac.uk/mail-www/haskell/msg00991.html
(Similar thing is "using namespace" in C++) (in Java, "import" does
really mean "use", since everything is "withed", but that "use" then has
to be global - presumably for the same reason that Ada-with must be
at the start of the module: for maintenance, dependence on
other modules should be clearly visible).

I think the current Haskell definition (import .. qualified .. hiding)
is kludgy. Especially "hiding": that sounds similar in spirit to
a subroutine call  of the kind "call function f but don't execute its
fourth statement".

(PS: now it's enough kidneys from me)
-- 
-- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 --
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