Mailman 3 May 2019 - Python-ideas

Re: [Python-ideas] Operator as first class citizens -- like in scala -- or yet another new operator?
by Chris Angelico May 22, 2019

May 22, 2019

On Wed, May 22, 2019 at 10:03 PM Yanghao Hua <yanghao.py(a)gmail.com> wrote: > > To be first-class citizens, operators would have to be able to be > > passed to functions - for instance: > > > > def frob(x, y, oper): > > return x oper y > > assert frob(10, 20, +) == 30 > > assert frob(10, 20, *) == 200 > > > > The nearest Python currently has to this is the "operator" module, in > > which you'll find function versions of the … [View More]

6 8

Operator as first class citizens -- like in scala -- or yet another new operator?
by Yanghao Hua May 22, 2019

May 22, 2019

> Perhaps you might be able to do what you want using an import hook. I have done some experiments with introducing some new operators that way: https://github.com/aroberge/experimental/blob/master/experimental/transform… Thanks for the link, it is a very interesting module. I have to confess there is one more level of intention I have not talked about ... it is about analyzing the python VM code and translate it to C++/SystemC/Verilog or even doing direct synthesis to hardware basic … [View More]

1 0

Operator as first class citizens -- like in scala -- or yet another new operator?
by Yanghao Hua May 22, 2019

May 22, 2019

> If you are proposing to add "<-" and "->" to the fundamental Python > grammar, then it could work as PEP465 does. But if you are proposing > that classes can define new lexical operators, it would have to work > very very differently. You started with "operators as first class > citizens," but I don't know what you mean by that. It is my bad to mix this two topics together ... I am not strongly proposing for now to have python to support arbitrary operator definitions, … [View More]

1 0

Fwd: Operator as first class citizens -- like in scala -- or yet another new operator?
by Yanghao Hua May 22, 2019

May 22, 2019

On Wed, May 22, 2019 at 2:54 PM Rhodri James <rhodri(a)kynesim.co.uk> wrote: > > On 22/05/2019 13:29, Yanghao Hua wrote: > > Problem is python do not allow you to define new operators in the > > language itself, except those pre-defined you can modify their > > behavior. Even in case, if python would have been able to allow me to > > redefine the behavior of "=", e.g. by checking if the left hand side > > has a method (e.g. __assign__) to override the … [View More]

1 0

DB-API support for sets?
by Skip Montanaro May 22, 2019

May 22, 2019

The DB-API doesn't support sets directly, so you wind up having to manually expand them: >>> curs.execute("select count(*) from sometable where somecol in ?", ({4126,11638},)) Traceback (most recent call last): File "<stdin>", line 1, in <module> sqlite3.OperationalError: near "?": syntax error >>> curs.execute("select count(*) from sometable where somecol in (?)", ({4126,11638},)) Traceback (most recent call last): File "<stdin>", line 1, in <module&… [View More]

5 4

Passing positional arguments as keyword arguments (to provide function arguments out of order)
by Robert Vanden Eynde May 16, 2019

May 16, 2019

Currently if one wants to provide positional arguments after keyword arguments, it's not possible, one must begin with positional arguments [1] or use keyword arguments [2] : ``` def f(x, *, long_name='foo'): return ... f(2, long_name='bar') # [1] f(long_name='bar', x=2) # [2] ``` The problem is that it's not always possible to do so because some functions cannot have keyword arguments (because they call a C function) like math.hypot : ``` import math math.hypot(y=5, x=2) # TypeError ``` … [View More]

6 10

A plea for people to please remember to assume good faith
by Steven D'Aprano May 16, 2019

May 16, 2019

In another thread, a couple of days ago, there were a few ill-tempered[1] accusations thrown around about "rudeness" and "attitude". Please remember that email is notorious for communicating tone of voice very badly. Especially if people overcompensate by trying hard to be extra polite, which makes the tone come across as formal and patronizing. Face to face: "Dude, you need to read the docs." (Yes, I do!) Email: "You need to read the docs." (Really?) Hyper-polite email: "Perhaps you … [View More]should consider reading the docs." (Oh, I do, do I? What makes you so sure of that you patronizing git?) I know I have a bad habit of over-compensating. Sorry. It is hard to get tone right without slipping too far one way or the other, and phrases which sound "just right" in your head, and the first five times you re-read the email before hitting Send, can sound harsher than intended an hour later. And remember that the writer's attitude is an internal mental state, and judging it from email is not even close to easy or accurate. I mean, sure, you can probably guess the attitude of the author of abusive emails: "Dear Bob, you're a poopy-head filled with poop and your head is poop, you poop." but generally it isn't safe to try to guess the writer's attitude. It is especially not welcoming, considerate, friendly etc etc etc to assume bad faith based on a medium as infamous for leading to over-reactions and misunderstandings as email. So please: - try to assume the author of emails is writing in good faith - especially if the email is trying to express a friendly tone with smileys or winks to soften the tone (give them credit for the attempt even if you think it wasn't enough) - but even without them, it may not always be wise to assume that just because a sentence comes across as cold or harsh that it was intended that way - assume small slights are inadvertent or accidental, not attacks - in mild or borderline cases, don't assume that your judgement of tone is accurate - even if it is, try not to escalate the situation - try to respond to what they say rather than how they say it - and don't make the mistake of thinking that others aren't judging your tone exactly the same way you are judging theirs. They might be just too polite to call you out on it. Even if we *correctly* judge something was intended as a rebuke or snark, so what? Does it matter? We shouldn't be so hyper-sensitive that any and every "insult" requires retaliation. Remember the Englightenment values of *dignity culture* where small slights are beneath our dignity to respond: "Dignity does not depend upon reputation but exists as unalienable rights that do not depend on what other people think of one's bravery. Having a thick skin and shrugging off slights become virtues because they help maintain social peace." https://reason.com/2015/09/11/victimhood-culture-in-america-beyond-dig/ And for the record, I completely acknowledge that I do not always live up to these ideals. [1] And here I am, judging tone and attitude from emails. I know. -- Steven [View Less]

2 1

easier lazy logging in stdlib ?
by mak apuf May 16, 2019

May 16, 2019

Hello all, Let's consider logging.debug(expensive_function()) There are a few possibilities to run an expensive function when logging only if the log is effectively output : - eager formatting + calling by using fstrings or .format(expensive_func()) - formatting being done lazily by separating the log string from the arguments (by using % syntax which is dated maybe) - creating a Lazy object that calls expensive_func when calling its __str__ method, but that it a bit cumbersome because you … [View More]

3 2

(meta) Mailman cleartext passwords
by Tom Hale May 14, 2019

May 14, 2019

When I signed up, I got an email with subject: Welcome to the "Python-ideas" mailing list It included the text: ====================================================================== You must know your password to change your options (including changing the password, itself) or to unsubscribe without confirmation. It is: my-cleartext-password ====================================================================== This has bugged me about Mailman in the past... luckily I used a … [View More]

2 1

(meta) Mailman list searching
by Tom Hale May 14, 2019

May 14, 2019

How do I search this list's archives? I can't see any search functionality at: https://mail.python.org/pipermail/python-ideas/ Using the other archive recommended recently: https://code.activestate.com/search/lists/?sa=Search&list=python-ideas#q=ma… Gives me: The Google Web Search API is no longer available. Please migrate to the Google Custom Search API (https://developers.google.com/custom-search/) -- Tom Hale

2 2