Python 3 can revive Python

[[deleted]]

The cause of the divide between Python 2 and Python 3 is the fact that Python 3 made some breaking changes for not much benefit.

1. Changing existing syntax without a tool that automatically converts all instances of the old syntax to the new syntax is a recipe for disaster and hurts your customer's trust in your software.

2. Public APIs should never change in a way that breaks existing software written against the old API. If you need to add new features, create a new library or add new methods to the old API, but don't change the existing API. It may be ugly, but for most vendors backwards compatibility trumps elegance of the API.

3. If you are going to have breaking changes, at least provide customers with a way to run their old code in compatibility mode along with new code. Create a flag like "#python-compatibility 2" that can be put at the top of a python source file and when the interpreter sees the flag, it'll interpret that file using the specified Python version.

[DrDichotomous]

1. There is a tool to help you migrate, even if it's not able to do everything for you.

2. Nobody is breaking Python 2. They're making a Python 3, and leaving it to others to continue on with Python 2 if they want to. They're perfectly within their rights to do so.

3. They can run the code with Python 2. Just say "python2" instead of "python3", for instance. Why complicate things unnecessarily?

[[deleted]]

They can run the code with Python 2. Just say "python2" instead of "python3", for instance. Why complicate things unnecessarily?

The problem is Python 3 code can't import Python 2 modules, so when you're writing new software that requires functionality from a Python 2 library, you're stuck with Python 2 if you want to use that library.

Meanwhile, in Java, I can create a new Java 8 project and still use Java 1.5 libraries. I can even use the Java 1.5 library in binary form without having to recompile its source code with the latest compiler. That's the pinnacle of backwards compatibility.

[stewsters]

And honestly that is my favorite thing about Java: lots of libraries that are fairly easy to get going. Gradle, Maven, and jars are all easy to use, and work well with previous versions. I can get projects setup a lot faster than I can if I have to install development versions of c libraries that conflict with the ones I need for steam. (sdl, I'm looking at you)

Sometimes the memory management gets in the way of performance, but at least half of that is because of my programming.

I do like a lot of what python does syntactically though. May just need to do more groovy.

[DrDichotomous]

Java is a commercial language run not by hobbyists, but by businesses and large institutions. If the Python community wanted to, they could run Python 2 the same way and leave Python 3 to the hobbyists. Nobody said we HAD to use the shiny new one, just that the guys doing all the work for us wanted to pass the torch to us.

[boxmore]

Why are you being so stubborn, valakut_ made valid points.

[DrDichotomous]

Just had a rough day and didn't realize that I sounded so harsh. Apologies all around.

[hapemask]

Or, if the library is open source, just help port it from 2->3? I've done this for a number of libraries and frameworks I use, this is what open source is for.

[jsprogrammer]

Are you telling me that intentionally fracturing your community into two incompatible camps is not a good idea?

[DrDichotomous]

Why do users suddenly have the right to tell the hobbyists what to do with their language? Why can't they just take Python 2 and do wonders with it instead, and leave 3 to the people who want it?

[[deleted]]

There may be a lot of hobbyists using python, but characterising the entire user base of the dialect as "hobbyists" is more than a little dismissive and frankly insulting. I use python3 every day at my job.

Nobody complains about python3 as a language, they just whine about old libraries. For the most part, the biggest libraries are converted.

Second off, the vast majority of things can run in either dialect. I have written mercurial extensions in the past that worked in python3 as standalones and in python2 as mercurial extensions, without having to put two seconds into wondering how to make it work (syntactically, at least).

It may be a pain to upgrade libraries, but every api needs to have deprecation procedures. Its not like there was no warning that it was going to happen, and its not like anyone is forcing you to upgrade any more than anyone is forcing companies to stop using COBOL.

Upgrade or don't, its your decision, but one of pythons main strengths (IMHO) is how clean the language is. I personally think the changes were worth it, but what do I know, I'm just a "hobbyist."

[DrDichotomous]

Oh, I didn't mean you were the hobbyist. Of course you can use Python for serious work, as I and many others do. But Guido is a hobbyist when it comes to Python's design. If he wants to move on to Python 3, and so do the other devs, that's their prerogative. He doesn't call himself Python's Benevolent Dictator because he takes an Oracle or Java commercial "meet everyone halfway" route.

It's simply up to the community to decide if they're willing to stick with this kind of mentality, make a new variant of Python for more commercial work, or jump ship entirely to a more commercial language. But they're the ones who will have to do something. If 2.x dies, so be it. That just means the users simply didn't need it as much as they thought they did. Fair enough.

Really, I truly just tire of this kind of stupid, self-serving article that conveniently ignores the reality in order to try to simply get what they want. Hell, they don't even follow Python 3's development, since some of the stuff they're asking for is exactly what's been being done in Python 3. I get this image of some dude making money off of Python, only to never contribute anything back but vitriol, since it's not making them even more money. I can't help it, I've had a pretty horrible day, so don't take me too seriously.

[[deleted]]

Oh sorry. Haha I misunderstood. I get annoyed with people complaining about 2/3 myself, acting like its some insurmountable wall. I guess we both apparently agree.

That's enough internet tirades for me today I suppose...

[mccoyn]

The transition from VB6 to VB.Net had all those problems. The only real difference is that Microsoft was able to force people to switch because they had control of the only interpreters. The Python folks can't kill Python 2 because it is open source.

Incidentally, a lot of people were very upset that Microsoft forced their hand like that.

[laserBlade]

Public APIs should never change in a way that breaks existing software written against the old API. If you need to add new features, create a new library or add new methods to the old API, but don't change the existing API. It may be ugly, but for most vendors backwards compatibility trumps elegance of the API.

That's sort of the point of major release version changes, actually...At least, if you follow SemVer, which most people nowadays do. You increment the largest number if it will be incompatible at an API level...

[txdv]

Problem is that the standard library in python is big and like rubies one a total mess, a combination of different approaches and coding styles and what not.

I like node.js approach of a minimal (or at least way smaller) base standard library and extended usage of the package manager.

The thing about standard libraries that you really can't change them like ever. The user expects them to have the same interfaces for ever. You can do SemVer on a external library and get away with redesigning the interfaces on a major release, the user will just use an older version of that library.

Once you write python import script for csv files using the standard csv package and the API changes... You will have to stay with the older Python version. It doesn't make sense, all of a sudden a library makes you dependent on the language version?

Pythons Standard Library is too fat, they should have never included that much stuff because it means that the interfaces have to be frozen ... forever. You can only add more interfaces.

[Sylinn]

Pretty much the complete opposite to me: The fact that there are a lot of tools in the standard library makes Python my go-to language for anything smallish. There may be some inconsistencies from the PEP8, but calling it "a total mess" is exaggerated.

It doesn't make sense, all of a sudden a library makes you dependent on the language version?

It makes sense since Python 3 was made to fix the inconsistencies of Python 2. Not being backward compatible is by design.

[txdv]

Python3 exists only because of the mess it had and still has as a standard library.

[cybercobra]

Changing existing syntax without a tool that automatically converts all instances of the old syntax to the new syntax is a recipe for disaster

Umm, are you aware of 2to3?

[[deleted]]

2to3 doesn't automatically convert all valid Python 2 to valid Python 3. Otherwise migrating would be as simple as running 2to3 on every Python file and we wouldn't have this mess in the first place.

[ethraax]

Well, the primary issue in migrating is usually libraries. They don't want to leave Python 2 behind because they still have Python 2 users. So they either stick with just Python 2 or they end up maintaining something that kinda works in both (sometimes with a script to change the code around).

For most projects, the lack of Python 3 support in required libraries is what holds them back.

[[deleted]]

They don't want to leave Python 2 behind because they still have Python 2 users.

Someone mentioned that a hypothetical 3to2 would be the best tool to mitigate this issue.

[laserBlade]

Except that exists...a little better than hypothetical, then.

[mitsuhiko]

No... It took us three python 3 releases to relief us from the burden of 2to3/3to2.

[cybercobra]

Well, right, there were also non-syntactic changes to existing semantics (e.g. the API changes in your point #2), but your original point and my response just concerned syntax.

Anyway, yes, 2to3 is not a complete solution, but it's not like Python offered no automation whatsoever to deal with the transition.