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Go ahead and look at those breaking changes, then compare with Python 2 to 3's breaking changes. It's a difference of a few minor things versus a whole swath o

Go ahead and look at those breaking changes, then compare with Python 2 to 3's breaking changes. It's a difference of a few minor things versus a whole swath of changes to the handling of strings in the language, heck, a python 2 print statement isn't compatible with python 3. These are much more significant breaking changes which make porting code much harder than any of the other examples you've given. For the most part, developers don't have to touch or only have to make minor changes for specific cases to port to Ruby 1.9 or C++11 - look at those C++11 changes for example, so few people were doing those things and they're such bad practices that it simply didn't matter. They successfully preserved compatibility in the nominal case. But even following all the best practices in your Python 2 code will not make it run under Python 3.

chc 9y ago
I don't use Swift or C++ much, but I have several years of experience in both Ruby and Python. The changes in Python might be a bit bigger, but the changes in Python 3 and Ruby 1.9 seem of roughly the same magnitude to me. Text encoding is now a problem you need to think about, some methods were removed, other methods were added, the output of some methods changed (e.g. the output of Array.to_s, the result of indexing a string), a few syntactic constructs changed (e.g. character literals used to return numbers, now return strings), and all C-based libraries broke in Ruby 1.9. In both cases, more than 99% of your code will probably be the same (unless your program is mostly print statements, I guess). What's more, Python took more pains than Ruby to ease the upgrade process, with stuff like __future__ imports, 2to3, and the six library. IIRC the Ruby team just changed stuff and said, "OK, update your code accordingly and we promise not to do this to you again for a long time." It seems to me like the primary difference that made the Python upgrade worse is that the authors of the big libraries in Ruby were enthusiastic about moving to Ruby 1.9, so that it was possible to start porting most Ruby apps very soon after 1.9 released, while a few big Python library authors dragged their feet on even getting started. This was a very real problem, but it was essentially a cultural problem of the library landscape being very different, not a matter of the language itself being drastically different.

chc 9y ago

I don't use Swift or C++ much, but I have several years of experience in both Ruby and Python. The changes in Python might be a bit bigger, but the changes in Python 3 and Ruby 1.9 seem of roughly the same magnitude to me. Text encoding is now a problem you need to think about, some methods were removed, other methods were added, the output of some methods changed (e.g. the output of Array.to_s, the result of indexing a string), a few syntactic constructs changed (e.g. character literals used to return numbers, now return strings), and all C-based libraries broke in Ruby 1.9. In both cases, more than 99% of your code will probably be the same (unless your program is mostly print statements, I guess). What's more, Python took more pains than Ruby to ease the upgrade process, with stuff like __future__ imports, 2to3, and the six library. IIRC the Ruby team just changed stuff and said, "OK, update your code accordingly and we promise not to do this to you again for a long time." It seems to me like the primary difference that made the Python upgrade worse is that the authors of the big libraries in Ruby were enthusiastic about moving to Ruby 1.9, so that it was possible to start porting most Ruby apps very soon after 1.9 released, while a few big Python library authors dragged their feet on even getting started. This was a very real problem, but it was essentially a cultural problem of the library landscape being very different, not a matter of the language itself being drastically different.