From: Joel VanderWerf <vjoel@...>
Date: 2009-04-11T14:22:26+09:00
Subject: Re: a few thoughts for ruby...

Roger Pack wrote:
> Thought I'd pass these thoughts by the readers here before sending them
> to core.  They're my current wish list :)
> 
> 1) add an Object#in? method to complement the existing Array#include?

It's not really symmetrical. Array has an #include? method because it is 
a collection. Object has #in? because it is--what? A potential member of 
a collection?

This would conflict with lots of potential other uses of #in? that have 
nothing to do with collections:

Clutch#in?

Doctor#in?

Fix#in?

(to start just with the 0-ary ones).

> 2) add some useful lists of exceptions, ex: IO.SELECT_EXCEPTIONS,
> IO.READ_EXCEPTIONS, so that you can rescue the wide gamut of them
> appropriately, should you desire to.

I've wanted that, and ended up with:

   ALL_NETWORK_ERRORS = [Errno::ECONNRESET, Errno::ECONNABORTED,
     Errno::ECONNREFUSED, Errno::EPIPE, IOError, Errno::ETIMEDOUT]

   ALL_NETWORK_ERRORS << Errno::EPROTO if defined?(Errno::EPROTO)
   ALL_NETWORK_ERRORS << Errno::ENETUNREACH if defined?(Errno::ENETUNREACH)

Maybe a better way would be to include a module, AnyNetworkError, in 
each of these. Then you could

  rescue AnyNetworkError

Like this:

module E; end

class E1 < StandardError; include E; end
class E2 < StandardError; include E; end

begin
   raise E1, "foo"
rescue E => ex
   p ex
end

> 4) (this one's controversial) remove the extra # for code in strings
> (i.e. "string#{code}") -> "string{code}" less typing.

Would not like having to escape { in strings...

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407