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What’s New in Python 3.8

docs.python.org

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Re: What’s New in Python 3.8

#51

Post by jfim »

BurningFrog wrote: post #32
robocat wrote: post #30

def f(a, b, /, c, d, *, e, f): Wow: IMHO that is a very ugly syntax to define a fn with 6 parameters, although it looks to be a path dependency on previous decisions (*, and CPython ,/) and clearly there was much discussion of the need for the functionality and the compromises: https://www.python.org/dev/peps/pep-0570/ It amazes me to see how certain features make it into languages via community/committee (octal numb…

> which itself is a result of limiting ourselves to the ASCII symbols that can be typed I think we're ready for programming languages using some visually good Unicode characters, instead of overloading `[]{}!@#$%^&*()-_/` for everything!

Many languages allow that. Scala allows characters in the math symbols (Sm) and other symbols (So) Unicode categories as identifiers for functions and variables, and APL has a rich notation that relies on many single character operators.

Re: What’s New in Python 3.8

#52

Post by peterwwillis »

CivBase wrote: post #22

As a developer who has primarily developed applications in Python for his entire professional career, I can't say I'm especially excited about any of the "headlining" features of 3.8. The "walrus operator" will occasionally be useful, but I doubt I will find many effective uses for it. Same with the forced positional/keyword arguments and the "self-documenting" f-string expressions. Even when they have a use, it's us…

Perl devs have been using the walrus expression for decades, but we just called it "assigning a variable with local scope in an expression".

  $ perl
    $a = "foo";
    if ( my $a = "bar" ) { print "$a\n" }
    print "$a\n"
  bar
  foo

Re: What’s New in Python 3.8

#53

Post by jimktrains2 »

Rebelgecko wrote: post #40
metalliqaz wrote: post #2

This is the release that contains the controversial assignment expressions, which sparked the debate that convinced GvR to quit as BDFL. They didn't select my preferred syntax, but I'm still looking forward to using assignment expressions for testing my re.match() objects. I haven't used 3.8.0 yet but I hope its a good one because 2020 is the year that 2.7 dies and there will be a lot of people switching.

>They didn't select my preferred syntax I don't write much python so there's probably something obvious I'm missing, but I don't see why they didn't use "=". Is there some significant difference between assignment expressions and assignment statements that makes it worth having distinct syntax?

Yes, there is.

    If x = 1
Has been the source of many errors in many languages. Forcing assignment to be more than a 1 character difference from the equality operator prevents this.

Re: What’s New in Python 3.8

#54

Post by seunosewa »

egdod wrote: post #37
ageofwant wrote: post #28

Earlier quoted context omitted.

I take this as a positive sign of Python's maturity.

Mature languages don’t introduce random new ugly syntax. I miss Guido already.

Actually, Guido approved the walrus operator. (In response to the justified backlash, instead of canceling the feature, he resigned as BDFL, which is not what anyone wanted)

Re: What’s New in Python 3.8

#56

Post by robocat »

BurningFrog wrote: post #32
robocat wrote: post #30

def f(a, b, /, c, d, *, e, f): Wow: IMHO that is a very ugly syntax to define a fn with 6 parameters, although it looks to be a path dependency on previous decisions (*, and CPython ,/) and clearly there was much discussion of the need for the functionality and the compromises: https://www.python.org/dev/peps/pep-0570/ It amazes me to see how certain features make it into languages via community/committee (octal numb…

> which itself is a result of limiting ourselves to the ASCII symbols that can be typed I think we're ready for programming languages using some visually good Unicode characters, instead of overloading `[]{}!@#$%^&*()-_/` for everything!

There are programming fonts that use ligatures to convert >= to ≥, or -> to →, so the source code remains in ASCII but symbol sequences show as unique Unicode characters.

A next step could be for common dev environments to actually convert symbol/key sequences to operators (how do APL programmers do it?)

Avoiding ambiguity and semantic overloading of ASCII symbols would surely help beginners (if also given a UI that clearly exposes ways to enter the new symbols). I always find one letter operators extremely strange too like u"word" s/foo/bar/ etc.

It seems a shame we can type in hundreds of Unicode symbols on a mobile virtual keyboard, but not readily on a physical keyboard.

JavaScript has supported Unicode for a long time, but the core language doesn't use it at all.

Re: What’s New in Python 3.8

#57

Post by jimktrains2 »

diminoten wrote: post #25
mistrial9 wrote: post #16

Earlier quoted context omitted.

the emotional content outweighs the objective situation here; also humorous since Luddites are commonly misunderstood per https://en.wikipedia.org/wiki/Luddite

Not misunderstood; luddites (lowercase l, or at least the generalized form) means something different than Luddites (capitalized L).

I'm fairly certain the lowercase l version is the same, but the Luddites are remembered as being ant technology, not pro labour.

Re: What’s New in Python 3.8

#58

Post by closed »

kolinko wrote: post #39
CivBase wrote: post #22

As a developer who has primarily developed applications in Python for his entire professional career, I can't say I'm especially excited about any of the "headlining" features of 3.8. The "walrus operator" will occasionally be useful, but I doubt I will find many effective uses for it. Same with the forced positional/keyword arguments and the "self-documenting" f-string expressions. Even when they have a use, it's us…

I actually found an immense use for Walrus - used it to hack Python into doing pattern matching that is way more readable than without it: https://github.com/eveem-org/panoramix (source code for Eveem.org, which is arguably the best decompiler for Ethereum smart contracts out there. you can see a lot of pattern matching in pano/simplify.py , and I found no way to do it without extending the language/walrus while main…

This is super interesting! I've never seen codecs used to introduce language features like this... Do you have any good references for getting started with using codecs?

Also, I wonder if there's an easy way to implement this in a jupyter notebook, without fiddling with the kernel...

(issues of whether it's a good idea aside, definitely seems useful to know about.. )

Re: What’s New in Python 3.8

#59

Post by amanzi »

rapfaria wrote: post #43
amanzi wrote: post #27

Real Python have a great post out today going through most of the changes: https://realpython.com/python38-new-features/ They have a lot of code samples and examples about how and when to use the new features.Personally, I love the new debugging support in F strings.

Too bad I'm losing good articles like this one because of those patronizing, click-baity newsletters that they started sending out a year or two ago.

They appear to have toned down their marketing efforts recently. You no longer get bombarded with clickbait pop ups or alerts.

Re: What’s New in Python 3.8

#60

Post by w-m »

> The list constructor does not overallocate the internal item buffer if the input iterable has a known length (the input implements __len__). This makes the created list 12% smaller on average. (Contributed by Raymond Hettinger and Pablo Galindo in bpo-33234.)

Wow. I believe it's a stated goal of CPython to prefer simple maintainable code over maximum performance. But relatively low-hanging fruit like this makes me wonder how much overall CPython perf could be improved by specialising for a few more of these.

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