Talking about glue languages reminds me how much I dislike languages that cannot easily call components written in anything else. Guess that gets only worse when you get proud of it and call the idea "Pure Something" :-))).
For a real-world example, I really would like to integrate one of those Java-based UML tools with a COM-based project management tool: both have a complex object model based on different technologies, and getting the two to talk is a lot more work than I'm wanting to do. Looking around for some library to make it easier is not the answer: it's still too much work. I want this kind of gluing to be a snap.
I like the idea of a compiler switch enforcing strict compatibility and portability constraints and stuff like that. But I don't like the idea of building a platform that is inherently poor at any form of interaction with anything else.