[glenjamin]

I've never been massively keen on the carious implementations of ruby, they're all a bit different and those differences appear to be documented poorly. This is most visible if compared to the python landscape.

[tierack]

I don't have a handle on the Python implementation landscape, but the various Rubies all regularly contribute to rubyspec[0] and report on how they're doing. And with rvm[1] it's incredibly easy to test code across rubies. From where I'm sitting, it seems dead simple to find the differences and how they could affect me.

0: https://github.com/rubyspec/rubyspec 1: http://rvm.beginrescueend.com/

[glenjamin]

I admit I perhaps haven't looked into this as much as I perhaps should have before making that claim.

My understanding is that the rubyspec project (http://rubyspec.org/), is an effort to retrospectively document all the stuff the language does.

Compare ruby: http://eigenclass.org/hiki.rb?Changes+in+Ruby+1.9, to python: http://docs.python.org/dev/whatsnew/2.7.html

I appreciate this isn't a great example, as python 2.7 isn't a different implementation (ruby 1.8 -> 1.9 is though), but this has been my experience of the way things are documented language-wise.

[tedunangst]

I'm afraid that the only explanation I can formulate for your comment is that you are simply unaware of alternative python implementations, because the differences between rubies and pythons are documented approximately evenly.

[koenigdavidmj]

The Ruby approach is that you should have good enough unit tests to make sure that you can pass everywhere you want. That is also a generally good idea with other dynamic languages, as you get checks that the compiler provides on static languages (like making sure that if you renamed a method, you renamed calls to that method everywhere).