A6: Pipes

[Michael Lazzaro]

Since noone else has said it yet -- This Apoc looks *great*.  The sig 
stuff is very, very nice.  (The wrapper stuff has interesting 
possibilities, too, especially with OO.)

Question on pipes: I like very much the concept of relating them only 
to the variadic list, that was the piece we were all missing in the P6L 
discussions.  After reading that appendix, I'm still a bit murky on the 
final decisions as to which of these edge cases will be allowed:

         my @out <== (1,2,3);
         my @out <== (my @in = foo());
         my @out <== foo();
         (1,2,3) ==> my @out;
(my @in = foo()) ==> my @out;
           foo() ==> my @out;
Are these all valid, or do some of them have to be errors?  I got lost 
in the appendix explanation of what was confirmed, and what was 
wishful-only...

FWIW, stylistically, I'd personally vote for

   @in ==> map  {...}
       ==> sort {...}
       ==> map  {...}
       ==> @out;
as better than:

   @in ==>
       map  {...} ==>
       sort {...} ==>
       map  {...} ==>
       @out;
... if we care about such details.  :-)

MikeL