Yes, separate compilation, and since your language, as I understand it, will support receiving and using scraps from wherever, you'll have to deal with it too unless you insist on strictly source-code sharing only.
You see, those are eternal (well, perennial) problems with distributed code management and every language/computing platform has to deal with them somehow, so that's why I'm interested in what your approach is, especially so since you aim to "solve the software sharability problem".
For the (slow) interpreter, it's just a string. For the compiler, we may end up just using a string in the end too, and interning, and then doing identity equality on the pointer. This is especially cheap because we have small/in-pointer/immediate strings.
You see, those are eternal (well, perennial) problems with distributed code management and every language/computing platform has to deal with them somehow, so that's why I'm interested in what your approach is, especially so since you aim to "solve the software sharability problem".