I don't see a way around having duplicated calls to &$code. You can change the way you call &$code based on what your calling context wants. You can even make the destination dependant on what the calling context wants, but this will require you to test wantarray twice; once to determine the lvalue and once to make the correct rvalue call.

$code = sub { wantarray ? ('foot','ball') : 'soccer' };

sub foo {
    my ($r, @r);                          # two possible returns
    (wantarray ? (@r) : ($r)) =           # slight of hand to get the 
+correct lvalue 
        (wantarray ? (&$code) : &$code);  # and make the correct rvalu
+e call
    return $r || @r                       # return that which is defin
+ed
}

$x = &foo();
@x = &foo();

print $x;
print @x;
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This gives you the ability to do something after your call to &$code. If you did not need this, you could more susictly say:

$code = sub { wantarray ? ("foot","ball") : "soccer" };

sub foo { wantarray ? (&$code) : &$code }

$x = &foo();
@x = &foo();

print $x;
print @x;
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