IDEA: lexically scoped subs anyone

[Piers Cawley]

Did anyone suggest the following yet?

    package Foo;

    my sub _helper_function { ... }

    sub public_function {
        ...
        helper_function(...);
        ...
    }

    # Some other file:

    use Foo;

    Foo::public_function(@args);  # Okay
    Foo::_helper_function(@args); # Throws an exception/dies

Is it possible? Advisable? 

-- 
Piers