The biggest mistake Python 3 made was the print statement change. There was really no compelling reason to do it, it broke basically 2.x script ever for 0 practical gain.
From what I've seen the unicode/string bytes/chars is a much bigger factor. Ironically this change made my largest Python app easier in Python 3 (easier to embed unicode literals from various languages), so perhaps my opinion isn't so valid here...
edit: sorry I hit "flag" instead of "parent" when trying to navigate back, hope that didn't affect anything (I've since unflagged)
If they wanted print-as-function, fine, but they didn't have to eliminate the print statement at the same time.
Some warts you're better off not scratching at.
> the print was more like a little fuck you to maintenance devs everywhere
> If they wanted print-as-function, fine, but they didn't have to eliminate the print statement at the same time.
Complete and utter hyperbole. You could read PEP-3105 [0] and easily see it isn't true. In addition to this, quoting from both the PEP and the docs [0][1]:
> "Luckily, as it is a statement in Python 2, print can be detected and replaced reliably and non-ambiguously by an automated tool, so there should be no major porting problems (provided someone writes the mentioned tool)."
> "When using the 2to3 source-to-source conversion tool, all print statements are automatically converted to print() function calls, so this is mostly a non-issue for larger projects."
Enough with the bullshit.
[0] https://www.python.org/dev/peps/pep-3105/ [1] https://docs.python.org/3/whatsnew/3.0.html
Now you can use python-future instead, a third-party solution, but the 2to3 part of the PEP was a false promise that gave ammo to Python 2 fans.
The PEP (3105) doesn't actually mention 2to3 anywhere, it just says that the fact that print is a statement (ie handled explicitly in the language syntax) means it is easy to write a tool to do the conversion automatically. Which is a perfectly valid point, even if 2to3 fails to do that for some reason.
There is no added benefits to have done that. They are just not listening. Now, Pythons 2/3 are sufferin despite being one of best language out there.
For god's sake, it is subtle, but not that hard to understand. There are added benefits. For one thing, consistency. Why is `sys.stdin.write()` a function but `print` isn't? What happens if you want to replace `print` with your own function, e.g. for logging? With a print function, you can just reassign that function, with a statement, you can't. What's the effect of this switch on the bytecode/parsing code? All the arguments against it seem to come down to "I don't like it".
> being one of best language out there.
Why is Python one of the best languages out there? Ease of use through consistency. Surely that's just an argument for `print()`.
Python3 allowed the devs to fix some of the mistakes or sins of the past, similarly `input`/`raw_input`. In the short term, it's maybe a bit of hassle. In the long run, not at all. 2to3 handles this mostly, but you can use `from __future__ import print_function` to test it in Python2. Nobody is refusing to switch to Python3 because of `print` alone.
In addition, the hack is already there:
Python 3.5.2 (default, Dec 2015, 13:05:11)
[GCC 4.8.2] on linux
print "hello"
Traceback (most recent call last):
File "python", line 1
print "hello"
^
SyntaxError: Missing parentheses in call to 'print'
Finally, the print stuff was one of the main reasons I pick Ruby over Python for my startup 5 years ago. I may be alone but I don't think so. And I think I make the right decision. Look at the some of the latest benchmarks Ruby vs Python. Python is now lagging strongly behind when it was ahead 5 years ago with 2.7. The 3.x branch keeps making weird decisions.
It's not hard. This isn't some arbitrary bracket hate or love, it's how the language syntax works at it's core: statements (e.g. if, el, in) never have brackets, function invocation always has. Simple!
So what am I not understanding? That you are proposing some other syntax, e.g. function invocation without brackets? That you don't like breaking changes? That you'd keep everything as it was for sake of habit? Python 3 breaks Python 2 in many ways, but okay. Any other coherent arguments why `print` should remain a statement?
> Finally, the print stuff was one of the main reasons I pick Ruby over Python for my startup 5 years ago
There are enough things to not like about Python 3. But do not get me started on Ruby. A language that constantly breaks stuff between minor version numbers (1.8 -> 1.9, 1.9 -> 2.0, etc)? Way to undermine your own argument.
Edit: To append this infamous article about a Ruby migration 1.8.7 to 1.9.3 (http://www.darkridge.com/~jpr5/2012/10/03/ruby-1.8.7-1.9.3-m...), lest I be accused of Ruby bashing. Of course, the original article we're discussing mentions Ruby in the same breath with Python 3. Oh, the irony of trying to put down Python 3 by citing Ruby.
You're right, a print() statement is better than just print, but it was an unnecessary change, that was made 'for the best' without sufficient justification.
Python3 allowed the devs to fix some of the mistakes or sins of the past
It was too many changes, all at once.
I think the lesson here is that time and time again, 'big bang' breaking changes have been failures.
2to3 should have made this a trivial change; but that only holds if 2to3 actually worked for every other simultaneous breaking change (it didn't).
A far, far more mature and better approach would have been the 3.x line being a continual stream of breaking changes with a flawless 2to3 that converted 100% of every python2 program to working python3, and a series of 3.xto3.y migrations that flawlessly upgraded python3 code until all breaking changes had been worked out.
Imagine if you had a series of transformations you could apply to any python2 project and you could incrementally migrate it automatically to 3.5. That is what we should have had. Screw print statements; invest in meaningful stuff when you make breaking changes.
Yes, this is indeed a problem. You could argue the Macbook Pros also suffer from this. But at some point, you've got to make the changes. Since Python 3 was already a breaking change, is it better to suffer a bit more in the short term and lay the foundations for the future?
In a way, this trade-off of short-term vs long-term is what responsible people do every day. Brushing your teeth, going to college, etc. Sometimes the easy path is the wrong one. Most religions are fairly clear on this, too ;) But it does rely on a (perceived) gain in the future. For some people, Python 3 just isn't a great gain. And to be honest, it's only in later 3.* versions we've seen the really useful things. Even then, for some people Python 2 was enough, just like for some people bash is enough, or 640k or memory.
It's still a hard question, one with no definitive answer. Economically speaking, does one major port cost more than multiple breaking changes over time? You might think spreading the cost out is better, but this only works if reputation doesn't suffer. Which is, again, very hard to quantify.
But we're kind of past all of this. Python 2 is legacy, Python 3 is still actively developed. It isn't a discussion worth having, because it isn't a discussion anymore. Maybe next time (Python 4 anybody?), we can look back and learn something.
I just want people to know why it was changed, that there was some thought behind it, and that it wasn't arbitrary. Python Enhancement Proposals are easily my favourite "feature" of Python.