Christian Tismer-Sperling writes:

I thought this list would always stay intact as an alternatice to the web things. How sad!

The list is alive. You got an immediate answer, did you not? It's just that almost all of the people who are engaged with discussion every day have found alternative platforms more productive. Partly because that's where the other discussants are (the network externality is undeniably powerful), and partly (I believe) because effective use of email is a skill that requires effort to acquire. Popular mail clients are designed to be popular, not to make that expertise easy to acquire and exercise. Clunky use of email makes lists much less pleasant for everyone than they could be. I guess that's sad (I am, after all, a GNU Mailman developer), but it's reality. Steve

On 02.08.23 18:30, Paul Moore wrote:

On Wed, 2 Aug 2023 at 15:24, Stephen J. Turnbull <turnbull.stephen.fw@u.tsukuba.ac.jp <mailto:turnbull.stephen.fw@u.tsukuba.ac.jp>> wrote:

Partly because that's where the other discussants are (the network externality is undeniably powerful), and partly (I believe) because effective use of email is a skill that requires effort to acquire. Popular mail clients are designed to be popular, not to make that expertise easy to acquire and exercise.  Clunky use of email makes lists much less pleasant for everyone than they could be.

I guess that's sad (I am, after all, a GNU Mailman developer), but it's reality.

Personally, I'm sad because some people whose contributions I enjoy (you being one of them :-)) didn't move to Discourse. But like you say, it's how things are.

Christian - you can make named constants using class attributes (or an enum):

class A:     M = "M"

match seq:     case A.M, A.M, A.M, A.M, *r:         return 4*1000, r

Basically, the "names are treated as variables to assign to" rule doesn't apply to attributes.

I'm not sure how helpful that is (it's not particularly *shorter*) but I think the idea was that most uses of named constants in a match statement would be enums or module attributes. And compromises had to be made.

Cheers, Paul

Thanks a lot, everybody! I have tried a lot now, using classes which becomes more readable but - funnily - slower! Using the clumsy if-guards felt slow but isn't. Then I generated functions even, with everything as constants, and now the SPM version in fact out-performs the regex slightly! But at last, I found an even faster and correct algorithm by a different approach, which ends now this story :) Going to the Discourse tite, now. Cheers -- Chris -- Christian Tismer-Sperling :^) tismer@stackless.com Software Consulting : http://www.stackless.com/ Strandstraße 37 : https://github.com/PySide 24217 Schönberg : GPG key -> 0xFB7BEE0E phone +49 173 24 18 776 fax +49 (30) 700143-0023

Hi Steve, Yes I am well aware that this regex example is not well suited for SPM. This was a proof of concept. Pushing things no the extreme is my way of understanding things deeply, so this was something I needed. For some reason, I love and hate regex. I hate it because it is unpythonic, char only and ugly. I love it because it is fast, and by the use of the verbose flag also quite readable. But getting rid of regex in favor of something even more capable was a long-standing wish that is yet not fulfilled, because the nature of both features is (still) pretty different. I would love to have similar building blocks as in regex, but with a pythonic syntax, and extending the basic string matching to general objects. At the moment I don't see this in SPM because there are basic flexible patterns missing. The only flexible thing in sequences is the star operator, but in my example this is always eaten by the need of an open end in the pattern. This is something that might improve. As a drive-by, while looking into the Pilgrim algorithm for Roman literals, I found by chance a faster algorithm :) Not only that my SPM craziness is now really faster than the regex solution, but I found something better, based on Pilgrim's `toRoman` part of the algorithm :D Given one of the basic algorithms in the internet which are fast and incomplete, this here is much faster than using regex: def from_roman_fastest(numeral): if numeral == 'N': return 0 num = from_roman_numeral(numeral) cmp = roman.toRoman(num) if numeral != cmp: raise InvalidRomanNumeralError(f"Invalid Roman numeral: {numeral}") return num This follows the old observation "Listening is much harder than talking", so this algorithm does not try a complex solution, but uses a simple one and checks if the input string was correctly reconstructed. Cheers -- Chris On 02.08.23 22:30, Steve Holden wrote:

Hi Chris,

Nice to see you on the list.

While this is definitely off-topic, I trust I might be given license by the list's few remaining readers to point out that the match-case construct is for _structural_ pattern matching. As I wrote in the latest Nutshell: "Resist the temptation to use match unless there is a need to analyse the _structure_ of an object."

I don't believe it's accidental that match-case sequence patterns won't match str, bytes or bytearrray objects - regexen are the tool already optimised for that purpose, so it's quite impressive that you are managing to approach the same level of performance!

Kind regards, Steve

On Wed, 2 Aug 2023 at 18:26, Christian Tismer-Sperling <tismer@stackless.com <mailto:tismer@stackless.com>> wrote:

On 02.08.23 18:30, Paul Moore wrote: > On Wed, 2 Aug 2023 at 15:24, Stephen J. Turnbull > <turnbull.stephen.fw@u.tsukuba.ac.jp <mailto:turnbull.stephen.fw@u.tsukuba.ac.jp> > <mailto:turnbull.stephen.fw@u.tsukuba.ac.jp <mailto:turnbull.stephen.fw@u.tsukuba.ac.jp>>> wrote: > >     Partly because that's where the other discussants are (the network >     externality is undeniably powerful), and partly (I believe) because >     effective use of email is a skill that requires effort to acquire. >     Popular mail clients are designed to be popular, not to make that >     expertise easy to acquire and exercise.  Clunky use of email makes >     lists much less pleasant for everyone than they could be. > >     I guess that's sad (I am, after all, a GNU Mailman developer), but >     it's reality. > > > Personally, I'm sad because some people whose contributions I enjoy (you > being one of them :-)) didn't move to Discourse. But like you say, it's > how things are. > > Christian - you can make named constants using class attributes (or an > enum): > > class A: >      M = "M" > > match seq: >      case A.M, A.M, A.M, A.M, *r: >          return 4*1000, r > > Basically, the "names are treated as variables to assign to" rule > doesn't apply to attributes. > > I'm not sure how helpful that is (it's not particularly *shorter*) but I > think the idea was that most uses of named constants in a match > statement would be enums or module attributes. And compromises had to be > made. > > Cheers, > Paul

Thanks a lot, everybody!

I have tried a lot now, using classes which becomes more readable but - funnily - slower! Using the clumsy if-guards felt slow but isn't.

Then I generated functions even, with everything as constants, and now the SPM version in fact out-performs the regex slightly!

But at last, I found an even faster and correct algorithm by a different approach, which ends now this story :)

Going to the Discourse tite, now.

Cheers -- Chris -- Christian Tismer-Sperling    :^) tismer@stackless.com <mailto:tismer@stackless.com> Software Consulting          : http://www.stackless.com/ <http://www.stackless.com/> Strandstraße 37              : https://github.com/PySide <https://github.com/PySide> 24217 Schönberg              :     GPG key -> 0xFB7BEE0E phone +49 173 24 18 776  fax +49 (30) 700143-0023

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-- Christian Tismer-Sperling :^) tismer@stackless.com Software Consulting : http://www.stackless.com/ Strandstraße 37 : https://github.com/PySide 24217 Schönberg : GPG key -> 0xFB7BEE0E phone +49 173 24 18 776 fax +49 (30) 700143-0023