The MARC data structure, and the AACR2 rules that usually accompany it, are strange beasts. Every once in a while I’m asked why I get so frustrated with them, and I explain that there are things — strange things — that I have to deal with by writing lots of code when I could be spending my time trying to improve relevancy ranking or extending the reporting tools my librarians use to make decisions that affect patrons and their access. This is one of those tales. I’m a systems librarian, which in my case means that I deal with MARC metadata pretty much all day, every day. Coming from outside the library world, it took me a while to appreciate the MARC format and how we store data in it, where appreciate can be read as hate hate hate hate hate. I find it frustrating to deal with data…