Still exploring what can be done with lvalue subs in closures, I came to realize that the trinary operator is also an lvalue. It may be used as a switch for access to different cloistered lexicals. Consider 

{
    my ($foo,@foo);
    sub foo () :lvalue {
        wantarray ? @foo : $foo;
    }
}

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foo becomes the accessor for both the scalar and the array. The ordinary rules of context apply: 
foo = 'Flintstone';
(foo) = qw/Fred Wilma Pebbles/;
# Hmmm, odd bug, the lines following demonstrate what works
# print scalar(foo), ', ', $_, $/ for foo;
print join ' & ', foo;
print ' ', scalar(foo),$/;

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More complicated practices are possible. The scalar might be a coderef, to be called on the array.

Something special can happen in void context, by using a defined wantarray ? : ; term in the accessor, though the options are limited by each term's need to be an lvalue. Here a scalar closure is undefined by being called in void context: 

{
    my $foo;
    sub foo () :lvalue {
        defined wantarray ? $foo : undef $foo;
    }
}

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This is just exploration, not part of a project. What can you think of to do with it?

After Compline,
Zaxo

In reply to More Lvalue Subs - Double-Barreled Closures by Zaxo

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