checked-exceptions-cont

[marcinczenko]

Continuation of #1179.

First part:

• get rid of the old AsyncIter in favor of SafeAsyncIter
• rename SafeAsyncIter -> AsyncIter after replacement

After that there will be separate PR that aims at replacing all remaining {.async.} with something closer to {.async: (raises: [CancelledError]).}. I decided to split the PR as otherwise we may miss some important things related to erasure coding that should be reviewed.

[dryajov]

Actually, thinking about this now, maybe we should leave both SafeAsyncIter and AsyncIter, it doesn't seem like they can be unified easily and it does seem like AsyncIter could be useful on it's own.

[marcinczenko]

@dryajov

Actually, thinking about this now, maybe we should leave both SafeAsyncIter and AsyncIter, it doesn't seem like they can be unified easily and it does seem like AsyncIter could be useful on it's own.

I am hesitating a bit, but perhaps we could keep the old AsyncIter. If we want to keep it, we probably should change the names. For now I have renamed the SafeAsyncIter to AsyncIter (so that it is the default). Now if we decide to resurrect the old AsyncIter we should reconsider the naming: maybe let's call it UnsafeAsyncIter or AsyncIterWithExceptions or ThrowingAsyncIter or RaisingAsyncIter? What do you think? In any case I feel that the name AsyncIter should be used by the default one. I am also fine with keeping the old naming: SafeAsyncIter for the new one that is used, and AsyncIter for the legacy one which is not currently used anymore.

Another thing - If we decide to keep the old AsynIter - is that we should probably refactor it slightly, as some of its types are borrowed from regular sync Iter so it was even missing proper .async. annotations. It is just a bit legacy code.

Or even better, and something you also mentioned I think - perhaps, it is best to move them to a separate package in a separate repo - both of them in the same repo I suppose: something like "nim-async-iterators".

Please take a look also at codex-storage/codex-pm#238 for some naming proposals.

Let me know what do you think.

[marcinczenko]

I have aligned the tree iterators, improved separation between them (so that e.g. AsyncIter does not reuse Iter's types that are not meant for asynchronous calls), and I made sure that the annotations are more align with "modern" Nim. Thus in the end we have three iterators: Iter, AyncIter (one that can throw exceptions), and AsyncResultIter (one that uses Result to communicate errors and failures). From those three, AsyncIter is currently not in use. They are all ready to be extracted to a separate Nim package.

[cnanakos]

Great work!