From: Yukihiro Matsumoto <matz@...>
Date: 2007-02-17T23:20:48+09:00
Subject: Re: Oppinions on RCR for dup on immutable classes

Hi,

In message "Re: Oppinions on RCR for dup on immutable classes"
    on Sat, 17 Feb 2007 22:51:06 +0900, Stefan Rusterholz <apeiros@gmx.net> writes:

|With current implementation, the only way to figure if an object can be 
|dup'ed is by dup it and catch the exception. I don't know how imperative 
|duck-typing is for ruby, but this way actively prohibits it.

As far as I understand, DuckTyping is not something based on method
existence, but something letting them raise error without explicit
type checking.

|As said before, the issue can be worked around (as you say e.g. via 
|exception handling), but following your argument, my question would be: 
|why implement a method that can't be executed?

We haven't implemented a method that can't be executed.  Object#dup
just fails if the object is not able to be duped.  Am I missing
something?

							matz.