sub huge_function {
    my $many, $variables, ...;

    # do something

    # do something else
}

##</code><code>##

{
    my $many, $variables, ...;   # accessible inside all closed over subs here

    sub previously_huge_function {
       # set $many ...

       do_something();

       do_something_else();
      
    }

    sub do_something {
        my $internal_var;
        # access $many...
    }

    sub do_something_else {
        my $internal_var;
        # access $many...
    }

}