use strict;
use warnings;
use XML::LibXML qw( );
die "Usage" if @ARGV != 3;
my $parser = XML::LibXML->new();
my @counts;
{
my $doc = $parser->parse_file($ARGV[1]);
my $root = $doc->documentElement();
@counts = map $_->textContent, $root->findnodes('elem');
}
{
my $doc = $parser->parse_file($ARGV[0]);
my $root = $doc->documentElement();
for my $node ($root->findnodes('elem')) {
die "Not enough counts" if !@counts;
$node->appendText(
$node->textContent() x (shift(@counts) - 1)
);
}
print $doc->toFile($ARGV[2]);
}
die "Too many counts" if @counts;
Or if counts of 0 are acceptable:
my $new_text = $node->textContent() x shift(@counts);
$node->removeChild($_) for $node->findnodes('text()');
$node->appendText($new_text);
Tested.