inessential by Brent Simmons

Postel’s Law, RSS, and NetNewsWire

So, you might wonder, why is NetNewsWire’s RSS parser forgiving?

When I started writing NetNewsWire, there were other aggregators already out there that were forgiving.

For example, what happens when an RSS feed has an unencoded ampersand (and is thus not-well-formed XML)? Should NetNewsWire work around the error or not?

(Unencoded ampersands are possibly the most common of errors in RSS feeds.)

At the time I was writing the RSS parser, I believed it should try to work around the error, so it could read feeds that other aggregators could read.

Was that the right or wrong choice? It’s debatable.

But I do like that since Atom is a new format—and because NetNewsWire is already-established software—I have a chance to do it differently.