Hahaha, well, greet is a string constant. Its is not a variable; and strict says

"strict refs"
    This generates a runtime error if you use symbolic references (see
    perlref).

        use strict 'refs';
        $ref = \$foo;
        print $$ref;        # ok
        $ref = "foo";
        print $$ref;        # runtime error; normally ok
        $file = "STDOUT";
        print $file "Hi!";  # error; note: no comma after $file

    There is one exception to this rule:

        $bar = \&{'foo'};
        &$bar;

    is allowed so that "goto &$AUTOLOAD" would not break under
    stricture.
[download]