From: dblack@...
Date: 2006-11-18T02:23:10+09:00
Subject: Re: Referncing values of local variables

Hi --

On Sat, 18 Nov 2006, Thomas Luedeke wrote:

> I apologize in advance, because I know this gets asked again and again
> (and again.....) by newbies, but my searches don't show a clear answer,
> and none of my attempts work.
>
> This should be simple.  I want to define a constant,
>
>                             a = 3

That's not a constant; it's a local variable.  It sounds like you
might be running into scoping issues.

> then reference the value of a in arguments like,
>
>                   temp_array = Array.new(a)
>
>
> such that the temp_array is assigned a size of 3.
>
>
> This always seems to result in complaints about undefined local variable
> or methods.  Eval doesn't seem to make it work.

I suspect you're doing something like:

   a = 3
   def my_method
     temp_array = Array.new(a)
   end

where a has gone out of scope by the time you use it.

You can use a constant:

   A = 3

though that would normally be considered overkill, and bad design,
unless it's really a constant that needs to be defined outside of any
method, rather than a local variable or method argument.


David

-- 
                   David A. Black | dblack@rubypal.com
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org