Re: conditional self-execution

What you're describing sounds to me like a modulino.

Update: In a nutshell, the way it's done is something like this:

package Foo;

_run( @ARGV ) if ! caller;

sub _run {
    # Do stuff as a program
}
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It's using caller to tell whether it's being executed "at the top level". If you search for modulino on CPAN, there are a few examples to look at.