use warnings;
use strict;
use Math::GMP;
use Data::Dump qw/dd pp/;
use Data::Dump::Filtered qw/add_dump_filter/;

add_dump_filter( sub {
	my ($ctx, $objref) = @_;
	return { dump => "Math::GMP->new(\"$objref\")" }
		if $ctx->object_isa('Math::GMP');
	return; # normal dumping
} );

dd( Math::GMP->new("123"),
	Math::GMP->new("546745634563453111035453452346") );

__END__

(
  Math::GMP->new("123"),
  Math::GMP->new("546745634563453111035453452346"),
)