#!/usr/bin/env perl
use warnings;
use strict;
use 5.010;
use PPI;

my $raw = <<'__RAW__';
package FeeFi;
sub Fee {
	print "Fee\n";
}
sub Fi {
	print "Fi\n";
}
1;
__RAW__

my %sub_h;
{
	my $document = PPI::Document->new(\$raw)
		or die "oops!";
	$document->save('before');
	for my $sub (@{$document->find('PPI::Statement::Sub') || []}) {
		next if $sub->forward;
		$sub_h{$sub->name}{content} = $sub->content;
		my @elements = $sub->block->children;
		for (my $i=0; $i < @elements; $i++) {
			$elements[$i]->remove;
		}
	}
	$sub_h{''}{content} = $document->content;
}
{
	my $document = PPI::Document->new(\$sub_h{''}{content})
		or die "oops creating ''!";
	for my $stub (@{$document->find('PPI::Statement::Sub') || []}) {
		next if $stub->forward;
		# 1. store the document in its own variable
		my $doc = PPI::Document->new(\$sub_h{$stub->name}{content});
		my $sub = $doc->find_first('PPI::Statement::Sub');
		# 2. remove the sub element from its document
		$stub->insert_after($sub->remove)
			or warn "Can't insert_after!";
		# 3. remove the stub
		$stub->remove;
	}
	$document->save('after');
}