Re: [Python-ideas] Generator syntax hooks?

On 11 August 2017 at 15:13, Steven D'Aprano wrote: > On Fri, Aug 11, 2017 at 02:34:53PM +1000, Nick Coghlan wrote: >> This is another good reason why a termination condition would need to >> be checked before the filter condition rather than either after it, or >> only when

Re: [Python-ideas] Generator syntax hooks?

On Fri, Aug 11, 2017 at 02:49:10PM +1000, Steven D'Aprano wrote: > On Thu, Aug 10, 2017 at 01:25:24PM -0700, Chris Barker wrote: > > I guess I think of it like this: > > > > "if" is providing a filtering mechanism > > > > "while" is providing a termination mechanism > > > > -- is there a use

Re: [Python-ideas] Generator syntax hooks?

On Fri, Aug 11, 2017 at 02:34:53PM +1000, Nick Coghlan wrote: > This is actually how I came to the conclusion that if we were ever to > do something like this, the termination condition would need to go > *before* the filter condition: What if you want to check the filter condition before the

Re: [Python-ideas] Generator syntax hooks?

On 11 August 2017 at 06:53, Spencer Brown wrote: > The logical solution to me is to allow any order of while and if, and follow > the same 'rule' as multiple for loops - just nest/test those in that order. > Then you can have whatever priority you need. One question though is

Re: [Python-ideas] Generator syntax hooks?

On Thu, Aug 10, 2017 at 01:25:24PM -0700, Chris Barker wrote: > On Thu, Aug 10, 2017 at 8:39 AM, Paul Moore wrote: > > > > Also, there's a potential issue > > here - consider > > > > [expr for var in even_numbers() if is_odd(var) while var < 100] > > > > This is an

Re: [Python-ideas] Generator syntax hooks?

On 11 August 2017 at 01:39, Paul Moore wrote: > On 10 August 2017 at 14:42, Steven D'Aprano wrote: >> I don't think it is confusing. Regardless of the implementation, the >> meaning of: >> >> [expression for x in sequence while condition] >> >> should (I

Re: [Python-ideas] PyPI JSON Metadata Standardization for Mirrors

On Wednesday, August 9, 2017, Cooper Ry Lees wrote: > Hi all, > > First time emailer, so please be kind. Also, if this is not the right > mailing list for PyPA talk, I apologize. Please point me in the right > direction if so. > Here are some notes re: changing metadata:

Re: [Python-ideas] Generator syntax hooks?

On Thu, Aug 10, 2017 at 1:53 PM, Spencer Brown wrote: > The logical solution to me is to allow any order of while and if, and > follow the same 'rule' as multiple for loops - just nest/test those in that > order. > Actually, I think it would be better to only allow one

Re: [Python-ideas] Generator syntax hooks?

The logical solution to me is to allow any order of while and if, and follow the same 'rule' as multiple for loops - just nest/test those in that order. Then you can have whatever priority you need. One question though is how this should handle multiple loops - break all of them, or just the

Re: [Python-ideas] Generator syntax hooks?

On 10 August 2017 at 21:25, Chris Barker wrote: > On Thu, Aug 10, 2017 at 8:39 AM, Paul Moore wrote: > >> >> Also, there's a potential issue >> here - consider >> >> [expr for var in even_numbers() if is_odd(var) while var < 100] >> >> This is an

Re: [Python-ideas] Generator syntax hooks?

On Thu, Aug 10, 2017 at 1:03 PM, Terry Reedy wrote: > After all, we have "break" in both for and while loops, so clearly there is >>> the use case... >>> >> > In both cases, we use 'break' to mean break. If we want to break > comprehensions, I think we should continue to use

Re: [Python-ideas] Generator syntax hooks?

On Thu, Aug 10, 2017 at 8:39 AM, Paul Moore wrote: > Also, there's a potential issue > here - consider > > [expr for var in even_numbers() if is_odd(var) while var < 100] > > This is an infinite loop, even though it has a finite termination > condition (var < 100),

Re: [Python-ideas] Generator syntax hooks?

On 8/10/2017 9:42 AM, Steven D'Aprano wrote: On Wed, Aug 09, 2017 at 01:23:28PM -0700, Chris Barker wrote: I can't recall the use case(s) at the moment, but I have definitely wanted a way to break out of a comprehension -- and not always with infinite iterators. After all, we have "break" in

Re: [Python-ideas] PyPI JSON Metadata Standardization for Mirrors

The proper list for this would be distutils-sig as that's where packaging-related discussions typically occur. On Wed, 9 Aug 2017 at 21:22 Cooper Ry Lees wrote: > Hi all, > > First time emailer, so please be kind. Also, if this is not the right > mailing list for PyPA

Re: [Python-ideas] Generator syntax hooks?

On 2017-08-10 01:11 PM, Steven D'Aprano wrote: On Thu, Aug 10, 2017 at 12:39:34PM -0300, Soni L. wrote: I'm pretty sure I read somewhere that lambdas and generators share their syntax, and that syntax is already a subset of python syntax. Would it be too hard to expose that with a

Re: [Python-ideas] Generator syntax hooks?

On 2017-08-10 01:43 AM, Nick Coghlan wrote: On 10 August 2017 at 01:49, Soni L. wrote: On 2017-08-09 11:54 AM, Nick Coghlan wrote: Right, I was separating the original request to make "{x for x in integers if 1000 <= x < 100}" work into the concrete proposal to

Re: [Python-ideas] Generator syntax hooks?

On 10 August 2017 at 14:42, Steven D'Aprano wrote: > I don't think it is confusing. Regardless of the implementation, the > meaning of: > > [expression for x in sequence while condition] > > should (I believe) be obvious to anyone who already groks comprehension > syntax. The

Re: [Python-ideas] Generator syntax hooks?

On Thu, Aug 10, 2017 at 12:54:57AM +1000, Nick Coghlan wrote: Guido wrote: > > I haven't come around to this yet. It looks like it will make explaining > > comprehensions more complex, since the translation of "while X" into "if not > > X: break" feels less direct than the translations of "for x

Re: [Python-ideas] Generator syntax hooks?

On Wed, Aug 09, 2017 at 01:23:28PM -0700, Chris Barker wrote: > I can't recall the use case(s) at the moment, but I have definitely wanted > a way to break out of a comprehension -- and not always with infinite > iterators. > > After all, we have "break" in both for and while loops, so clearly