From: George Ogata <g_ogata@...>
Date: 2006-03-10T04:33:43+09:00
Subject: Re: [Newbie] Immutable objects

Einar <delete.ebuffer@delete.hotmail.com> writes:

> Robert Klemme wrote:
>> Einar H�st wrote:
>> It's not sufficient, you'll have to freeze those strings, too.  Note
>> that
>> this will freeze the originals which probably is a bad idea.  You could do
>> def ini(suit, rank)
>>   @suit = suit.dup.freeze
>>   @rank = rank.dup.freeze
>>   freeze
>> end
>>
>
> Ah, I see - in C# "where I come from", strings are immutable. Of
> course, no-one will be using this code except me, so I'm definitely
> conjuring imaginary problems here - but at the same time, the whole
> point of this project is to learn about the language :-)

For things like @suit -- which I take it can only take one of four
enumerated values -- I think it's actually more rubyesque to use
symbols.  e.g.:

  @suit = :spade

This has the side benefit that Symbols themselves are effectively
immutable.

But as Robert and James hinted, freezing is seldom used.  It's like
type-checking: you can be a complete nazi about banning anything out
of line, but (a) you lose elegance and simplicity of code and (b) your
tests should probably be checking this anyway.  YMMV.