You can use a reference to a anonymous sub inside your big subroutine.
For example, in this script the 'my' variables from the outer subroutine are visible inside $inner:

#!/usr/bin/perl

print outer('John', qw/dog car home/), "\n";

sub outer {
    my $name = shift;
    my @items = @_;
    my $inner = sub {
           return "$name\'s $_[0] ";
    };
    return map {$inner->($_)} @items;
}
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The example is quite silly, but i often use this technique to simplify code. It is useful, if $inner has no sense outside outer.