[munificent]

> clearly defined functions that take arguments and return values?

Sure, but what are the types of those arguments and return values?

If you call what I describe an anti-pattern, you're basically saying that packages can only interact using primitive types defined in the language. You can reuse code, but not data structures.

I think that's too much of a limitation. I want to reuse code that defines matrices, and vectors, and interesting collections, and business model objects like mailing addresses and currencies. I want to make games that use a mesh type defined in one package and pass it to a collision engine in another.

Saying "you can't use any user-defined type in any public API" is an incredibly harsh limitation, and what do you get for that in return? The ability to bloat your application with multiple versions of the same library?