From: Dave Burt <dave@...>
Date: 2005-09-04T23:06:27+09:00
Subject: Re: ruby / rails newbie - Finding documentation in RDocs

James Britt offered:
> steveH wrote:
>>   <% for column in Product.content_columns %>
>>     <th><%= column.human_name %></th>
>>   <% end %>
>>
>> but I can't find a description of class Column anywhere - can't see it
>> in rails docs, core ruby docs, MySQL/Ruby docs - have I just missed it
>> or is it somewhere else, or isn't it a class at all but some sort of
>> dynamic ruby magic which I've totally misunderstood...
>
> In the construct
>
>   for x in some.collection
>     ...
>   end
>
> x is a variable that takes on the file of each successive item in 
> collection.
>
> See [...]

James is right, there is no explicit type or class set for column, or indeed 
any Ruby variable. All Ruby variables have the dynamic ruby magic property 
of being able to hold an object of any type.

Here's some trivia realted to your question, though. For most or all of the 
connection adapters, content_columns will return an Array of Column, a.k.a. 
ActiveRecord::ConnectionAdapters::Column, which is a class in Rails, but 
doesn't appear in the API docs. It has properties: name, default, type and 
limit. You can read the source code for ConnectionAdapters, the 
AbstractAdapter, and the adapter for your database if you want to know more.

Cheers,
Dave