From: Surendra Singhi <efuzzyone@...>
Date: 2006-09-11T00:12:23+09:00
Subject: Re: Matrix modifying and coercion question?

Hi,
 I know it is bad posting on one's own email, but I didn't get any answer. I
feel these are reasonable questions to ask. Please help.

Regards,

Surendra Singhi <efuzzyone@netscape.net> writes:

> Hi,
>  I was wondering why Ruby Matrix class doesn't creates objects which are
> editable? 
>
> That is,
> m = Matrix[[2,3,4]]
> m[0,0]= 5
> NoMethodError: undefined method `[]=' for Matrix[[2, 3, 4]]:Matrix
> 	from (irb):11
> gives error,
>
> as a workaround I have seen people/myself opened the matrix class and defined the
> '[]=' method such that, '@rows' variable is edited.
>
>     def []=(i,j,val)
>       @rows[i][j] = val
>     end
>
> Is it safe to do this?
> Ditto for the Vector class? why are objects of these classes not editable?
>
> Second, if I want to change the class of an object? Is it possible to do so?
> Say, I want an object of Matrix class to automatically changed to DMatrix,
> which is a derived class, then how do I do so? 
>
> Thanks for your help.
>
-- 
Surendra Singhi
http://ssinghi.kreeti.com, http://www.kreeti.com
Read my blog at: http://cuttingtheredtape.blogspot.com/
,----
| "War is Peace! Freedom is Slavery! Ignorance is Strength!"
|     -- Orwell, 1984, 1948
`----