• Why it's stupid to `use a variable as a variable name` - part 1
• Why it's stupid to `use a variable as a variable name` - part 2
• Why it's stupid to `use a variable as a variable name` - part 3

According to "Programming Perl 3rd", p 263:

What happens if you try to dereference a value that is not a hard reference? The value is then treated as a symbolic reference.

In the line:

goto &{"greet"};
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"greet" is not a hard reference, so what happens when you try to dereference a value that is not a hard reference, e.g. {"greet"}? According to "Programming Perl", the string is treated as a symbolic reference. As far as I can tell, dereferencing the string "greet" is the very definition of a symbolic reference.

It's my understanding that my code tells perl to look in the symbol table for the name "greet" and return the appropriate part of greet's typeglob: the coderef part. On the other hand, a hard reference points directly at the data in memory so a hard reference doesn't need to access the symbol table to find the data.

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.
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It sure is a symbolic reference.

>perl -e"use strict 'refs'; ${'foo'} = 1;"
Can't use string ("foo") as a SCALAR ref while "strict refs" in use at
+ -e line 1.

>perl -e"use strict 'refs'; &{'foo'}"
Can't use string ("foo") as a subroutine ref while "strict refs" in us
+e at -e line 1.

>perl -e"use strict 'refs'; goto &{'foo'}"
Goto undefined subroutine &main::foo at -e line 1.
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You can dereference references and strings. We call the latter "symbolic references" because the reference is a symbol name rather than a true reference. It doesn't matter whether the string is returned from a variable, a string literal or some more complex expression.