Perl 6 and Perl 5 can at least be considered separate languages and separate ecosystems: Perl 5 is still under active development, not just for maintenance but for purposes of getting new language features.
It is somewhat confusing that these two languages differ by a number and not by name, but the intention is somewhat clear. In the case of Python, they seriously seem to believe that everyone is going to "upgrade".
The other thing about Perl 5 and Perl 6, is the backwards incompatibility gap is way large. And Perl 6 is designed such that Perl 16 shouldn't be necessary.
You can't really say the same thing about Python. If Python wants to remain in the game, I don't see how they can do it unless they are OK breaking backwards compatibility in another 6 years.
Python broke backwards compatibility for as simple a thing like a print statement. Nobody like to play stupid expensive migration games just because your language designer decided that print statement must be written a different way.
> Python broke backwards compatibility for as simple a thing like a print statement. Nobody like to play stupid expensive migration games just because your language designer decided that print statement must be written a different way.
That is a silly argument. They didn't break compatibility because they wanted to change the way print is. They changed the print because they already had decided to break compatibility. Ie "lets break compatibility to change print" vs "while we are breaking stuff, lets fix the print too"
In that case I'd say changing print would belong to the "trivial" end of the scale. Print function was backported to Python 2.6, so you can easily write code that is compatible with both. And modifying existing code is so trivial that even an automated tool (2to3) can do it reliably.
