[jtheory]

That surprised me as well; though perhaps it's just that "such as parsers" applies to more code than the author realized.

A parser is a discrete chunk of code that's general-purpose (likely to be called from lots of places with different content), but with a fairly straightforward list of cases that you can/should test to see how correct and robust it is.

There's a lot of code that fits into this category; not just parsers.