Simple merging of several and disjoint OBO ontologies from the same IDspace:
		
		
			use OBO::Parser::OBOParser;
			
			my $my_parser = OBO::Parser::OBOParser->new();
			my $result = OBO::Core::Ontology->new();
			
			$result->idspace_as_string("APO", "http://www.cellcycle.org/ontology/APO");
			$result->default_namespace("cellcycle_ontology");
			$result->remarks("Simple Merged Ontology");
			
			foreach my $onto_file (@ARGV) {
				my $ontology = $my_parser->work($onto_file);
				$result->idspace($ontology->idspace());
				$result->subsets($ontology->subsets()->get_set());
			
				foreach my $rel (@{$ontology->get_relationships()}){
					$result->add_relationship($rel);
					my $rel_type = $ontology->get_relationship_type_by_id($rel->type());
					$result->has_relationship_type($rel_type) || $result->add_relationship_type($rel_type);
				}
			
				foreach my $term (@{$ontology->get_terms()}){
					$result->add_term($term);
				}
			}
			
			$result->export();    # export back in OBO format the simple merged ontology