[Oberon] IMPORT Modules: why does order matter?

Jörg joerg.straube at iaeth.ch
Sun Mar 3 23:14:15 CET 2019


The important assumption in your description is „which does not change the interface“. As long as this is true, you don‘t have to reorder your original import sequence.
As long as X does not suddenly re-export things from Y everything is as expected. But this re-export thing would change the interface...


> Am 03.03.2019 um 16:13 schrieb Richard Hable <informujo at aon.at>:
>> On 03.03.19 00:13, Andreas Pirklbauer wrote:
>> But the question is whether one *should* allow imports to be declared
>> in *any* order. This could be endlessly debated...
> Really?
> To me it seems completely clear that the user of modules should *not*
> have to know about (hidden) implementation details like dependencies
> between those modules.
> Let’s say, I explicitly use the services of some third-party modules X
> and Y in my code. I import them in the order X, Y and everything works fine.
> One day, the implementor of X and Y decides to do a refactoring, which
> does not change the interfaces of the modules, but leads to a dependency
> between those modules: X now imports Y.
> And suddenly, for no good reason, my module does not compile anymore.
> Richard
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