From: stephen O'D <stephen.odonnell@...>
Date: 2009-04-09T05:40:06+09:00
Subject: Instantiate different class based on variable contents

Lets say I have a two classes, Foo and Bar.

In some code, I have a variable that can either contain the test 'Foo'
or the text 'Bar'.  If it contains Foo, I would like to call Foo.new
(v1, v2), if it contains Bar, I would like to call Bar.new(v1, v2).

Obviously I could create an IF statement, such as

if var == 'Foo' then
  Foo.new(...)
elsif var == 'Bar' then
  Bar.new(...)
end if

Or if I want to get fancy, maybe a dispatch table:

dispatch = {
  'Foo' => Foo,
  'Bar' => Bar
}

obj = dispatch[var].new(...)

Is there another Ruby way to do this sort of thing?

Thanks,

Stephen.