[Python-ideas] Re: PEP 584 (dict merge operators), dict.update and dict.gapfill

2019-12-27 Thread francismb
Hi Jonathan, On 12/27/19 3:16 PM, Jonathan Fine wrote: > Summary: dict.update(self, other) corresponds to 'merge-right'. Perhaps add > dict.gapfill(self, other), which corresponds to 'merge-left'. This post > defines dict.gapfill, and discusses update and gapfill in the context of > PEP 584. IMHO

Re: [Python-ideas] Code version evolver

2019-03-17 Thread francismb
On 3/15/19 11:09 PM, Chris Angelico wrote: > And, are you going to run this function on every single code snippet > before you try it? If just trying, may be not. But yes, if I care to know where the applicability limits are (interpreter versions) before integrating it. IMHO I don't think it's a g

Re: [Python-ideas] Code version evolver

2019-03-17 Thread francismb
On 3/15/19 11:09 PM, Chris Angelico wrote: > Python 3.5 introduced the modulo operator for bytes objects. How are > you going to write a function that determines whether or not a piece > of code depends on this? I'm not sure I understand the question. Isn't *a piece of code* that does a modulo oper

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-17 Thread francismb
On 3/15/19 9:02 PM, francismb wrote: > And the operator is the function.exactly, function application/call ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-17 Thread francismb
Hi Nick, On 3/12/19 3:57 PM, Nick Timkovich wrote: > The onus is on you > to positively demonstrate you require both directions, not him to > negatively demonstrate it's never required. >From Calvin I just wanted to have some examples where he sees a use for swapping operands (nothing to be demons

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
Thanks! On 3/15/19 8:56 PM, Chris Angelico wrote: > The same is true of books that discuss the language, blog posts giving > tips and tricks, Stack Overflow answers, and everything else that > incorporates code that people might want to copy and paste. What > version of Python do you need? What's t

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-15 Thread francismb
On 3/13/19 7:44 PM, David Teresi wrote: > `->` would not be ambiguous in the proposed cases, but it does already > mean something elsewhere in the language as of 3.5: > > def concat(a: str, b: str) -> str: > return a + b > > This could potentially cause confusion (as with the % operator being >

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
On 3/15/19 4:54 AM, Stephen J. Turnbull wrote: > The thing about "within 3" upgrades is that that kind of project-wide > annoyance is going to be minimal, because the language is mostly > growing in power, not changing the semantics of existing syntax. Such > changes are very rare, and considere

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
On 3/15/19 4:54 AM, Stephen J. Turnbull wrote: > What 2to3 does is to handle a lot of automatic conversions, such as > flipping the identifiers from str to bytes and unicode to str. It was > necessary to have some such tool because of the very large amount of > such menial work needed to change a

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
On 3/15/19 4:54 AM, Stephen J. Turnbull wrote: > Not really. For example, addition of syntax like "async" and "yield" > fundamentally changes the meaning of "def", in ways that *could not* > be fully emulated in earlier Pythons. The semantics simply were > impossible to produce -- that's why synt

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
Hi Greg, On 3/15/19 5:33 AM, Greg Ewing wrote: > Not really. Having to translate all your source every time a > minor version update occurs would be a huge hassle. PythonUAAS: upload the sources (zipped or packaged) and get them updated back ;-) Regards, --francis

Re: [Python-ideas] Code version evolver

2019-03-15 Thread francismb
On 3/14/19 9:47 PM, Chris Angelico wrote: > What happens when someone wants to support multiple Python versions? > "Requires Python 3.5 or newer" is easy. Forcing people to install the > correct one for each version isn't. What are the reasons why people want to support multiple Python versions,

Re: [Python-ideas] Code version evolver

2019-03-14 Thread francismb
Hi Paul, On 3/12/19 12:21 AM, Paul Moore wrote: > That sounds very similar to 2to3, which seemed like a good approach to > the Python 2 to Python 3 transition, but fell into disuse because > people who have to support multiple versions of Python in their code > found it *far* easier to do so with

Re: [Python-ideas] Code version evolver

2019-03-14 Thread francismb
Hi Steven, On 3/12/19 12:25 AM, Steven D'Aprano wrote: > I don't know who you expect is using this: the Python core developers > responsible for adding new language features and changing the grammar, > or Python programmers. Python core devs should write the 'python_next' and 'is_python_code' part

[Python-ideas] Code version evolver

2019-03-11 Thread francismb
Hi, I would like to discuss on the idea of a code (minor) version evolver/re-writer (or at least a change indicator). Let's see one wants to add a feature on the next version and some small grammar change is needed, then the script upgrades/evolves first the current code and then the new version ca

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-11 Thread francismb
Hi Greg, On 3/9/19 1:42 AM, Greg Ewing wrote: > Do you really want > to tell them that all their code is now wrong? Of course not, at least not so promptly. But, would it be still a problem if the update to a new version (let say from 3.X to next(3.X)) is done through some kind of updater/re-write

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-08 Thread francismb
Hi Oleg, On 3/3/19 4:06 PM, Oleg Broytman wrote: >You cannot create operator ``<-`` because it's currently valid > syntax: > > 3 <- 2 > > is equivalent to > > 3 < -2 Yes, its a good point, but for me it's not the same '<-' and '< -' due (n)blanks in between. It is may be how now it is

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-08 Thread francismb
Hi fhsxfhsx, On 3/4/19 5:56 AM, fhsxfhsx wrote: > Could you explain why do you prefer this operator than `+`? Well yes, because of the asymmetric operation done underneath (merging dicts is not symmetric). The asymmetry is explicit in the symbol. Not implicit from the documentation you need to kno

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-08 Thread francismb
Hi Calvin, On 3/4/19 2:09 PM, Calvin Spealman wrote: > I don't like the idea of arrows in both directions when you can just swap > the operands instead Well you saw just to examples of contexts (dict and bool). Could you imagine a context where swapping cannot be done and thus there is a need for

Re: [Python-ideas] Left arrow and right arrow operators

2019-03-08 Thread francismb
Hi Todd, On 3/4/19 2:18 PM, Todd wrote: > What is the operator supposed to do? this should depend on what you want to do, the type, the context. How to you would want to use it ? do you see a context where the symbols make meaning to you? Thanks in advance! --francis

[Python-ideas] Left arrow and right arrow operators

2019-03-03 Thread francismb
Hi, the idea here is just to add the __larrow__ and __rarrow__ operators for <- and ->. E.g. of use on dicts : >>> d1 = {'a':1, 'b':1 } >>> d2 = {'a':2 } >>> d3 = d1 -> d2 >>> d3 {'a':1, 'b':1 } >>> d1 = {'a':1, 'b':1 } >>> d2 = {'a':2 } >>> d3 = d1 <- d2 >>> d3 {'a':2, 'b':1 } Or on bools as M

Re: [Python-ideas] Dict joining using + and +=

2019-03-03 Thread francismb
On 2/27/19 7:14 PM, MRAB wrote: > Are there any advantages of using '+' over '|'? or '<-' (d1 <- d2) meaning merge priority (overriding policy for equal keys) on the right dict, and may be '->' (d1 -> d2) merge priority on the left dict over '+' (d1 + d2) ? E.g.: >>> d1 = {'a':1, 'b':1 } >>> d2

Re: [Python-ideas] Dict joining using + and +=

2019-03-03 Thread francismb
On 3/2/19 11:11 PM, MRAB wrote: > '<=' is for comparison, less-than-or-equal (in the case of sets, subset, > which is sort of the same kind of thing). Using it for anything else in > Python would be too confusing. Understandable, so the the proposed (meaning) overloading for <= is also too much/

Re: [Python-ideas] Dict joining using + and +=

2019-03-02 Thread francismb
On 2/27/19 7:14 PM, MRAB wrote: > Are there any advantages of using '+' over '|'? or for e.g. '<=' (d1 <= d2) over '+' (d1 + d2) ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct

Re: [Python-ideas] Dict joining using + and +=

2019-03-02 Thread francismb
On 3/2/19 8:14 PM, Raymond Hettinger wrote: > Lastly, I'm still bugged by use of the + operator for replace-logic instead > of additive-logic. With numbers and lists and Counters, the plus operator > creates a new object where all the contents of each operand contribute to the > result. With

Re: [Python-ideas] Generalized version of contextlib.close

2018-04-01 Thread francismb
On 03/26/2018 10:35 AM, Roberto Martínez wrote: > Hi, > > sometimes I need to use contextlib.close but over methods with a different > name, for example stop(), halt(), etc. For those cases I have to write my > own contextlib.close specialized version with a hard-coded method name. > > I think

Re: [Python-ideas] Dart like multi line strings identation

2018-04-01 Thread francismb
Hi, On 03/31/2018 09:47 PM, Terry Reedy wrote: > With no padding, I would not argue with someone who prefers > textwrap.dedent, but dedent cannot add the leading space. Couldn't one use use the 'indent' method on the 'textwrap' module for that purpose? Thanks, --francis _

Re: [Python-ideas] Add time.time_ns(): system clock with nanosecond resolution

2017-10-20 Thread francismb
Hi Victor, On 10/13/2017 04:12 PM, Victor Stinner wrote: > I would like to add: > > * time.time_ns() > * time.monotonic_ns() > * time.perf_counter_ns() > * time.clock_gettime_ns() > * time.clock_settime_ns() due nano vs. pico vs. ... why not something like (please change '_in' for what you like)

Re: [Python-ideas] PEP draft: context variables

2017-09-06 Thread francismb
Hi!, > Core concept > > > A context-local variable is represented by a single instance of > ``contextvars.Var``, say ``cvar``. Any code that has access to the ``cvar`` > object can ask for its value with respect to the current context. In the > high-level API, this value is given by t

Re: [Python-ideas] tarfile.extractall progress

2017-09-03 Thread francismb
Hi, >>> >>> For large archives, I want to display a progress bar while the archive >>> is being extracted with: >>> >>> >>> The callback can receive the tarinfo object and where it's being >>> extracted. This is enough to plug a progress bar >>> and avoid reinventing .extractall() >> >>What i

Re: [Python-ideas] Unittest error message failure context lazy creation

2017-08-27 Thread francismb
Hi Chris, Hi Steven, > Have you measured it, eg by replacing the message with a constant? By > what percentage does it speed up a successful test run? How far is significant for `one` test? Please exchange the zip method against `itertools.product` and some message creation with concatenation (us

[Python-ideas] Unittest error message failure context lazy creation

2017-08-26 Thread francismb
Hi all, while using `unittest` I see the pattern of creating an error message with the test context for the case that some `assert...` methods fails (to get a good error message). On the lines: class Test...(unittest.TestCase): longMessage = True def test_(self): ... for a, b, c ...