From: Ralph Shnelvar <ralphs@...32.com>
Date: 2009-11-06T01:10:41+09:00
Subject: Re: Freeze not freezing

Matz,

I deeply appreciate your answer.

But I will repeat part of the question: Is there a way to detect ...
in the general case ... that the reference to an object has changed?

In a more C-like environment, a debugger is able to detect (via
hardware) that a location in memory has changed.  Is something similar
available in Ruby?

Where is the Ruby debugger (watch, etc.) documented?

Ralph


Thursday, November 5, 2009, 7:14:11 AM, you wrote:

YM> Hi,

YM> In message "Re: Freeze not freezing"
YM>     on Thu, 5 Nov 2009 23:05:28 +0900, Ralph Shnelvar <ralphs@dos32.com> writes:

YM> |a) Is my reasoning correct?

YM> #freeze protect an object from modification.  The reference is not the
YM> target of freezing.

YM> |b) Is there a way to do what I want? That is, freeze f or c[0] so that
YM> |I get some sort of message/error/exception?

YM> You can protect an array (or object) as a whole, since it is an
YM> object, so that

YM>   c=[0,1]
YM>   c.freeze
YM>   c[0]=2    # => can't modify frozen array (RuntimeError)

YM> but you cannot freeze any variables.

YM> |c) Do my examples violate POLS?

YM> No.  Unlike C++, variables and references are not object in any sense
YM> in Ruby.  From my viewpoint, C++ violates POLS. ;-)

YM>                                                         matz.




-- 
Best regards,
 Ralph                            mailto:ralphs@dos32.com