Nested subroutines and Scoping in Perl

Question

I\'m writing Perl for quite some time now and always discovering new things, and I just ran into something interesting that I don\'t have the explanation to it, nor found it

Answer 1

The "official" way to create nested subroutines in perl is to use the local keyword. For example:

sub a {
    local *b = sub {
        return 123;
    };
    return b();  # Works as expected
}

b();  # Error: "Undefined subroutine &main::b called at ..."

The perldoc page perlref has this example:

sub outer {
    my $x = $_[0] + 35;
    local *inner = sub { return $x * 19 };
    return $x + inner();
}

"This has the interesting effect of creating a function local to another function, something not normally supported in Perl."