Am Do., 6. Sep. 2018 um 11:43 Uhr schrieb Petr Pudlák <petr.mvd@gmail.com>:
[...] Has some language explored this idea of making modules explicit as language-level objects? It seems that there could be some interesting possibilities, such as: [...]

You might want to have a look at Standard ML's signatures, structures and functors, they are probably what you're thinking about.

Cheers,
   S.