source: vendor/perl/5.8.8/pod/splitpod

#!/usr/bin/perl

use lib '../lib';  # If you haven't installed perl yet.
use Pod::Functions;

local $/ = '';

$level = 0;

$cur = '';
while (<>) {

    next unless /^=(?!cut)/ .. /^=cut/;

    ++$level if /^=over/;
    --$level if /^=back/;

    # Ignore items that are nested within other items, e.g. don't split on the
    # items nested within the pack() and sprintf() items in perlfunc.pod.
    if (/=item (\S+)/ and $level == 1) {
        my $item = $1;
        s/=item //; 
        $next{$cur} = $item;
        $cur = $item;
        $syn{$cur} .= $_;
        next;
    } else { 
        s,L</,L<perlfunc/,g;
        push @{$pod{$cur}}, $_ if $cur;
    }
} 

for $f ( keys %syn ) {
    next unless $Type{$f};
    $flavor = $Flavor{$f};
    $orig = $f;
    ($name = $f) =~ s/\W//g;

    # deal with several functions sharing a description
    $func = $orig;
    $func = $next{$func} until $pod{$func};
    my $body = join "", @{$pod{$func}};

    # deal with unbalanced =over and =back cause by the split
    my $has_over = $body =~ /^=over/;
    my $has_back = $body =~ /^=back/;
    $body =~ s/^=over\s*//m if $has_over and !$has_back;
    $body =~ s/^=back\s*//m if $has_back and !$has_over;
    open (POD, "> $name.pod") || die "can't open $name.pod: $!";
    print POD <<EOF;
=head1 NAME

$orig - $flavor

=head1 SYNOPSIS

$syn{$orig}

=head1 DESCRIPTION

$body

EOF

    close POD;

}