[jacobolus]

One of the basic marketing claims of the language developers is that one author's algorithm can be composed with another author's custom data type. If that's not really true in general, even for some of the most popular libraries and data types, maybe the claims should be moderated a bit.

[hatmatrix]

> one author's algorithm can be composed with another author's custom data type

This is true, and it's a powerful part of the language - but you can implement it incorrectly when you compose elements together that expect some attributes from the custom data type. There is no way to formally enforce that, so you can end up with correctness bugs.

[ekjhgkejhgk]

My experience is that it is true, if you throughly implement the interfaces that your types are supposed to respect. If you dont, well, thats not the languages fault.