Yes, I would assume the same issues would apply to any library. Lacking any "official" standard, ultimately you, or the library writer, will have decide what you want/need to support in terms of parsing the file entries.
RegEx is very powerful and flexible (there are entire courses devoted to nothing but RexEx programming) and quite worth the time invested in understanding how it works (at least on a basic level). I'm barely functionally literate with RegEx but I'm sure you can come up with one to parse TAG="VALUE" into groups that you can then parse into a map of (Tag, Value) entries. I also recommend
http://www.regxlib.com as a decent source for RegEx patterns that people have already created (although I did not find any M3U ones there).