From: david@...
Date: 2005-08-12T22:19:04+09:00
Subject: Re: Array redefinition problem

Cit�t Leslie Viljoen <leslie@camary.co.za>:

> Hello!
> 
> I have a large program which needs to be able to use Postgres OR MySQL.
> Since the MySQL module's query result has a num_rows method and Postgres
> returns an array, I thought I'd just redefine Array like this:
> 
> class Array
>  def num_rows
>    return length
>  end
> end
> 
> But in another line (@entries = Array.new) I get:
> 
> /var/www/ruby/core.rb:443:in `initialize': wrong number of arguments (0
> for 2) (ArgumentError)
> 
> Now if I do the same thing in a small test program, I get no errors.
> This works:
> 
> class Array
>   def num_rows
>     return length
>   end
> end
> 
> res = Array.new
> puts res.num_rows
> 
> In the large program I am not redefining Array anywhere else - what else
> can
> cause this error?
> 
> Les
> 
> -- 
> ruby -e "puts 'Just another fickle programmer'"
> 
> Leslie Viljoen    [leslie@camary.co.za]
> Camary Consulting [http://www.camary.co.za]
> Cellphone         [083-6186100]
> Personal web      [http://mobeus.homelinux.org]
> 
> 
> 
> 


If the Array redefinition is nested in a module, you are shadowing the builtin
Array class with a locally defined one. Try:

  class ::Array
    # Redefine methods.
  end

to make sure you're redefining the builtin one.