If you are running multiple automated eCommerce companies that have their core system written in Python 2 like I do, you'd find that boto/mws and python-excel aren't available for Python 3 (python-excel's porting to Py3 stopped in 2011), which would prevent you from spawning new businesses on Amazon or handling (unfortunately standard) MS Office interchange files quickly.
I actually made the decision to run on Python 2 due to unavailability of these libraries for Python 3 about a year ago (I didn't really care about Python before as I primarily used C++/Java/Asm/GLSL/C#/Haskell in the past) - I was deeply shocked by what Py3 did to its own community and still have that weird feeling that Python is slowly killing itself. I didn't want to write my own Amazon and MS Office wrappers in Python 3 anyway and from all platforms available Py2 seemed to have the least amount of troubles (though I had to write some Py3 code for handling advanced TLS properly).
yup. I think this is the reason so much eCommerce software is Java (& I'm sure there is a bunch of C# but that's not my thing). Java moves like a glacier but damn is it ever stable, and for those who wish to be "cutting edge" there is everything-under-the-sun on the JVM -- Clojure, Scala, Jython, JRuby, slimmer-by-the-minute Java APIs. And the community is just working their lil buns off trying to modernize this stuff while maintaining interop / backwards compatibility.
I think the flack Java gets is for not modernizing fast enough, but I think in a way that makes you stop and smell the roses (the roses being many years' worth of badass JVM features and massive flexibility/reliability in software development).
But Ruby & Python (I am an ex-Ruby guy) take this cutting edge thing wayyy too far & end up with a community of people who can't trust them anymore cuz they all had their damn feet shot off. Sometimes I see the rates for Ruby guys & wonder if they're high cuz its so productive or just cuz its very niche & the stack is shite. On principal, it's hard for me to imagine going back down that road after experiencing the JVM (plus, I'd like to get away from web one day...).
EDIT: Funny thing I just realized actually -- all the Ruby rates I've seen tend to be exactly on par with a lot of FUBAR niche near-extinct Java technologies. The only people I've seen do better than both these camps are down & dirty Linux/Oracle/Java guys. Maybe my view is skewed but I always feel like the rock-solid langs will live on & eventually "modernize" (though lets be real, modernize is kindof a BS term for slim API & lots of MVC tutorials). These other techs are at the mercy of market trends.
I worked at SUN in the distant past, the backwards compatibility was the mantra #1. Both latest Java and Solaris were expected to run the oldest possible code, and they considered it one of the most important assets.
For many people in eCommerce and banking the arrival of Java was a "manna from heaven", as before they had to deal with the crazy complexity of CORBA and similar technologies. Java simplified this significantly and added at the time modern easy-to-program and fairly safe multi-threading that allowed software like Apache etc. This made Java famous and gave it a "huge karma" amongst developers. Without Java we probably wouldn't have experienced the massive expansion of eCommerce, and now we are lucky to see all the Java's issues - a good problem to have ;-)
Java and JVM as a consequence have their share of problems that arose from initial design decisions such as type erasure (which .NET's CLR avoided) that still deforms all languages based on JVM to this day. Massive boilerplating, J2EE's unreadable XML mess, complex design patterns invented to cope with the limitations of the language are some of the other problems. The compatibility with the old code is still there though.
I've never played with Ruby, I've heard it's still used by many young web companies for their frontends (like SoundCloud) and have heard they had some release that broke most of the compatibility which alienated many of their users. From this and from Python's example I would suggest keeping both the old way and introducing the new ways in parallel so that developers don't have to rewrite/reinvent the wheel when somebody decides to change a part of the language. This served C/C++ pretty well, adding slowly new features and instead of forcing users to use the "current right way", they allowed to live multiple different approaches together. I think that would have served Python well as well - even Py3 feels at places like a hack, similar to Py2.
Java is simply becoming the next C. For a reason, in my opinion, since the languages share quite a few traits both on the language level and the ecosystem level. Both are fast. Both have a rock solid execution system which sometimes feels backwards compatible to the first punch card made of rock (gcc vs JVM). Both of them have huge communities having significant infrastructural services and other huge code bases developed in them (linux kernel, application servers, databases in both teams). The big improvement of java would be a higher programmer safety.
And to be fair, neither language is the prettiest, shiniest and fanciest for it's time, but they get the darned job done.
you (& bitL as well) make some fair points but I actually (maybe because I'm newer to Java?) have quite a different experience with it. The XML setup seems minimal now (sure it's all there but most stuff is now handled with reasonable default configs & annotations).
Take Jax-Rs is a good example. Once you understand it you're just like "Ohhhhh this is the same way Rails/whatever framework handles json requests but I can add in all this non-linear logic without forcing it to play nicely within a presumptuous design pattern". Adding many data sources & logic flows is easy.
Bottom line is that I feel like Java can never really be the next C because fundamentally its much safer and becoming way more human readable. It toes the line well -- you can code minimal stuff similar to the scripting languages, or you can drop years of work/research into optimization for high-transaction algorithms knowing that the platform won't abandon you.
(By the way, I am personally hoping for Clojure or node.js to take over the front-end of the stack & then just using Java to do any heavy lifting that is left over)
I just looked at that list and I see several prominent projects that (according to that list) don't support Python 3: MySQL-python, gevent, Twisted, eventlet, oauth2, thrift, nltk, mechanize, etc. I've used more than a few of these libraries over the years.
I mean, yeah, the list is getting smaller. That's understood. But that doesn't render the problem of depending on only-Python 2 libraries moot.
I think the fundamental insight of the OP is that Python X (the purgatory corresponding to code compatible with both Python 2 and 3) is an absolute pain to write. There's plenty you can do to make Python X easier (like the `six` library or ignoring Python 3.{0,1,2}), but the programmer is still left with the burden of writing code compatible with both versions.
There's just no denying that the Python 3 transition is a huge fucking pain that is costing people tons of time and money. With that in mind, it is absolutely reasonable that people are resisting the change.
Yes, I knew most of that. But the fact remains that they aren't complete yet and therefore can't actually be relied on as a dependency.
(N.B. I seem to recall someone telling me that gevent had been ported over a year ago and that all that remained was to just make a release. So count me skeptical until the port is complete.)
And that's just the most popular projects. Imagine what it looks like with the less popular projects? It isn't pretty. This is what the OP was talking about with the "tail" of Python projects.
N.B. I don't personally have this problem with less popular projects. I've always done my best to avoid depending on unmaintained or inactive projects because they tend to rot as time goes on (irrespective of massive changes like Python 2 and 3). But plenty of other people have this problem and it's definitely not an unreasonable problem to have.
Off the top of my head: Twisted and gevent. It was actually the lack of a Python 3 gevent that lead my to create one crucial piece of software for my startup using NodeJs communicating with the main Python application passing messages via Redis.
Look, I'm a Python 3 supporter, but you should never foist the Python 3 fork of gevent on anyone.
I'm pretty sure that, the monkey-patched way most people use it, it's a happy accident when gevent even works correctly on Python 2. This happy accident doesn't happen in an unofficial fork.
To clarify: NLTK develop branch is compatible with Python 3.2+ for more than a year. NLTK 3.0a4 (http://www.nltk.org/nltk3-alpha/) is not released as NLTK 3.0 because of some pending API changes, not because of Python 3 compatibility issues.
i use NLTK with python 3.4 (and before that, 3.3); NLTK has an alpha release for pyhthon 3; i have not had any problems either installing it or using it.
Ok so why would I risk hitting even one incompatible library or have stuff break because those are dev experimental, untested branches. Why? What does Python 3 offer me except risk of breakage?
Did you read the article? The long tail is the critical collection of libraries and most of them will never be ported. People write new Python 2 libraries every day, actually--the list is getting longer, not shorter. That said, gevent is an extremely critical library for a lot of production Python 2 code. There doesn't even seem to be a roadmap to port it to Python 3.
This is affecting other parts of Ubuntu, as we don't always install python2 anymore after porting all the default apps to python3. The lack of python3 launchpadlib means apport (the automatic bug reporting tool) doesn't work on some installations.
Let's assume a modestly sized Python program uses 8 libraries or so. Assuming 80% of libraries are ported, that means 20% aren't. The likelihood of at least one of your 8 libraries not being ported is 1 - (0.8)^8 = 83%. In other words, most people will find that at least one of their cricitcal libraries is not ported. That is certainly the case for me (Bloomberg Python API, for 2.7, and which, btw, only came out 6 months ago). Inevitably the people using Python come from specific domains, and use at least one domain specific library, so while all the common "usual suspect" libraries are ported, there is usually a very high chance that one critical library is not.
Perhaps the way the entire question should be thought of is: are there actually many properly useful Python 3 libraries that are not available in Python 2?? I bet the above equation would look much better when inverted.
There's a large number of significant commercial applications that use Python as their scripting and plug-in language. Non of them that I am aware of are showing any interest in Python 3.
I actually made the decision to run on Python 2 due to unavailability of these libraries for Python 3 about a year ago (I didn't really care about Python before as I primarily used C++/Java/Asm/GLSL/C#/Haskell in the past) - I was deeply shocked by what Py3 did to its own community and still have that weird feeling that Python is slowly killing itself. I didn't want to write my own Amazon and MS Office wrappers in Python 3 anyway and from all platforms available Py2 seemed to have the least amount of troubles (though I had to write some Py3 code for handling advanced TLS properly).