Hi Everyone,
I've been following the discussion on strong encapsulation with interest... It's a really interesting topic.
Reading through the posts and some of the Ruby books and documentation, I've come across the idea that Ruby's lack of strong typing is less important because there is some support for a unit testing framework.
My attention was grabbed by Jeff's response in the original thread, so instead of hijacking it, I thought it might be interesting to start a new discussion. I thought I'd kick things off with these points, sort of in order of priority:
Software engineering
o In our experience, putting well defined layers into the code has always helped clarify the system
o You can never tell what your users are going to do with your code! More protection is usually better 
o Clarity and reliability are almost always more important than speed
Testing in the real world
o Very often, only superficial testing is done, and this only catches the trivial stuff
o It's easy to catch the easy errors. To catch the hard ones takes a *lot* of work
o The late-breaking bugs are the ones that hurt - especially if it's a silly typo that could have been caught statically
Unit testing
o Often the problems crop up in integration rather than within a particular unit - having stricter checking on interfaces would really help
o It's hard to push a unit into all corners of it's functionality without reasonably fully fledged supporting functionality
o If the testbench suffers from the same limitations as the language it's testing, how do you know where the error's being generated?
Testing methodology
o There's a difference between syntax checking and verification of functional correctness
o Rigorous testing of software is often extremely hard to do, if not impossible - esp GUIs and large web apps
o Strict type checking can really help with the readability and maintainability of code
Just so you know where I'm coming from, I work verifying functional correctness of CPUs and designing the supporting tool flows. I have a strong disposition towards strong encapsulation, typing and testing, and even then I never do enough testing!
What do you all think?
Cheers,
Nick
