Should we support multiple versions of the same module installed on the system simultaneously?

[jfingerh]

The starting point of this proposal is "no". You cannot install different versions of a module on the system at once, and use both of them in the same program.

You can change your module path, and/or the module definitions in your module path, between runs of the compiler, and get different versions on different compiler runs, of course.

But you cannot have two different versions of a module used by the same program on the same compilation run.

[det-intel]

I wrote up a summary of the "hierarchical identifier reference" approach to namespaces and discussed the question of versioning in this Google doc: https://docs.google.com/document/d/1onMDxcgOgpCrUTDVKMq2UxHR7XL1mifBrktmQd2ecRU/edit?usp=sharing

Please comment on the doc or message me directly with questions or comments.