Re: [Async-sig] A modest terminological proposal
This is in reply to this message in the archives: https://mail.python.org/pipermail/async-sig/2016-October/000141.html Nathaniel Smith:
I've found that when talking about async/await stuff recently, I've mostly dropped the word "coroutine" from my vocabulary and replaced it with "async function". I'm writing to suggest that we might want > to make this switch as a community, and do it now, before the next 10x increase in the async/await userbase.
For what it's worth, I 100% agree.
*Accuracy*: Speaking of jargon, the term "coroutine" *is* an existing piece of jargon in computer science, and our term and their term don't quite match up. This isn't a huge deal, but it's unnecessary confusion. According to Wikipedia I guess technically we don't even have "true" coroutines, just "semicoroutines"? And every generator has just as much claim to being a coroutine-in-the-CS-sense as an async function does, but when we say coroutine we don't mean generators. (Except when we do.) This confusion might partly reflect the somewhat confusing transition from 'yield from' to async/await, as demonstrated by the official doc's somewhat confusing definition of "coroutine":
I've personally been very confused lately by python's terminology. I've always understood coroutines to have nothing a priori to do with event loops, scheduling. For example, I've understood coroutines as being objects that allow the following kind of flow (taken from https://en.wikipedia.org/wiki/Coroutine#Comparison_with_subroutines): var q := new queue coroutine produce loop while q is not full create some new items add the items to q yield to consume coroutine consume loop while q is not empty remove some items from q use the items yield to produce Python has basically supported this flow since 2.x (apart from the terminology issue of semi-coroutines mentioned above which I feel is relatively minor). This big point though is that being scheduled or asyncronous is kind of a separate property. Posix threads are implemented by feeding it a routine to start things off just like much of python's asyncronous stuff is built around coroutines, but I don't feel like the term "coroutines" should be merged into both just as routines aren't automatically tied to threads. Personally I think if anything the best possible comparison else where in computer science are the haskell thunks which delay execution until needed. That's the first thing I think about when I see how curio is setup for example. I recognize that it is very unlikely that this will change (hey language meaning changes over time), but I felt like I should reply after finding this thread because I personally have been very confused by the terminology used by python. (Personally I've been using coroutines by my definition for years using yield/send.) Thanks a lot for the write-up though. You saved my sanity a little bit... Cheers, Thomas
On Tue, Nov 29, 2016 at 11:39 AM, Thomas Nyberg <tomuxiong@gmx.com> wrote:
This is in reply to this message in the archives:
https://mail.python.org/pipermail/async-sig/2016-October/000141.html
Nathaniel Smith:
I've found that when talking about async/await stuff recently, I've mostly dropped the word "coroutine" from my vocabulary and replaced it with "async function". I'm writing to suggest that we might want > to make this switch as a community, and do it now, before the next 10x increase in the async/await userbase.
For what it's worth, I 100% agree.
...yes.
*Accuracy*: Speaking of jargon, the term "coroutine" *is* an existing piece of jargon in computer science, and our term and their term don't quite match up. This isn't a huge deal, but it's unnecessary confusion. According to Wikipedia I guess technically we don't even have "true" coroutines, just "semicoroutines"? And every generator has just as much claim to being a coroutine-in-the-CS-sense as an async function does, but when we say coroutine we don't mean generators. (Except when we do.) This confusion might partly reflect the somewhat confusing transition from 'yield from' to async/await, as demonstrated by the official doc's somewhat confusing definition of "coroutine":
I've personally been very confused lately by python's terminology. I've always understood coroutines to have nothing a priori to do with event loops, scheduling. For example, I've understood coroutines as being objects that allow the following kind of flow (taken from https://en.wikipedia.org/wiki/Coroutine#Comparison_with_subroutines):
I actually think this _is_ a bit of a big deal. Looking at things like: http://wla.berkeley.edu/~cs61a/fa11/lectures/streams.html#coroutines and (where generators were inspired from, for python) the Icon Programming Language book (e.g. co-expressions, and references to coroutines, e.g. p.119) http://www.cs.arizona.edu/icon/books.htm I think - really - async != coroutines, and (as others have said) muddies the waters, and kills some clarity. - Yarko
var q := new queue
coroutine produce loop while q is not full create some new items add the items to q yield to consume
coroutine consume loop while q is not empty remove some items from q use the items yield to produce
Python has basically supported this flow since 2.x (apart from the terminology issue of semi-coroutines mentioned above which I feel is relatively minor).
This big point though is that being scheduled or asyncronous is kind of a separate property. Posix threads are implemented by feeding it a routine to start things off just like much of python's asyncronous stuff is built around coroutines, but I don't feel like the term "coroutines" should be merged into both just as routines aren't automatically tied to threads.
Personally I think if anything the best possible comparison else where in computer science are the haskell thunks which delay execution until needed. That's the first thing I think about when I see how curio is setup for example.
I recognize that it is very unlikely that this will change (hey language meaning changes over time), but I felt like I should reply after finding this thread because I personally have been very confused by the terminology used by python. (Personally I've been using coroutines by my definition for years using yield/send.)
Thanks a lot for the write-up though. You saved my sanity a little bit...
Cheers, Thomas _______________________________________________ Async-sig mailing list Async-sig@python.org https://mail.python.org/mailman/listinfo/async-sig Code of Conduct: https://www.python.org/psf/codeofconduct/
participants (2)
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Thomas Nyberg -
Yarko Tymciurak