Thanks for the ideas. I'll chew on them a while and see how they digest. A quick note about your more succinct way. As I also noted in my reply to ikegami, an even more succinct way would be:

    sub foo { &$code }
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The context would propagate automatically.

Update: to prove it to myself, I ran the following code:

$ perl -le '
    my $code = sub {
       print wantarray
             ? "list"
             : "scalar" };
    sub foo { &$code }
    () = foo; foo'
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And it printed:

list
scalar
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Which verifies that the context propagates.