From: Charles Oliver Nutter <charles.nutter@...>
Date: 2008-12-05T06:41:42+09:00
Subject: [ruby-core:20325] Re: Leave my open classes alone (was Behavior: autoload calls rb_require()  directly)

Dave Thomas wrote:
> Please, no.
> 
> Every time we do something like this, we add more special cases to the 
> language. Right now, classes are open. We allow people to modify their 
> behavior. That's just Ruby. Take away plus, and you limit my freedom. 
> What's next? Maybe Fixnum.to_s. And then maybe Struct.to_s. And then 
> maybe all internal classes get closed, and no one would be able to 
> create things such as Symbol.to_proc.
> 
> I'd much rather see change going the other way. I'd like to see a = 
> "cat" calling String.new. I'd like to see fewer special cases.
> 
> If require is broken, then fix it. But don't stop me replacing it if I 
> want. And if I replace it incorrectly (making it not thread safe, for 
> instance) that then becomes my fault.
> 
> Ruby is about choice. If I wanted a language implementor to tell me what 
> I can change and what I can't change, I'd use Python or Java.

I can appreciate the "choice is good" argument, but I think the Ruby 
world needs a little less dogmatism about "choice" and "freedom" and 
"beauty". There's practical concerns here, concerns about API stability, 
thread-safety, performance, memory efficiency. Too many of those 
concerns are sacrificed on the altar of "choice" or "freedom".

In the case of core classes, we're not talking about closing them down 
completely; we're talking about guaranteeing to all developers and users 
that some minimum set of methods will do what you expect them to do, now 
and forever. We're guaranteeing that 1 + 1 will continue to == 2. And 
it's not the case where *you* want to override a core method that's the 
problem...it's the case where someone else overrides it--potentially by 
mistake--and you don't find out about it until later.

Ruby needs to grow up as a language by allowing people who want 
guarantees to get guarantees. And there's a lot of people who want some 
minimal, basic guarantees about core classes.

- Charlie