From: pjb@... (Pascal J. Bourguignon)
Date: 2009-03-29T23:40:05+09:00
Subject: Re: Dynamic object creation in ruby

Robert Klemme <shortcutter@googlemail.com> writes:

> On 29.03.2009 13:40, Brian Candler wrote:
>>> frank = Object.const_get("Master::Person").new("Frank")
>>>
>>> Does anyone know why the second way fails?
>> frank = Master.const_get("Person").new("Frank")
>
> Erm, that's a hybrid solution.  If you know the names beforehand, you
> can just do
>
> frank = Master::Person.new "Frank"

Then the answer for the OP would be:

frank = Object.const_get("Master").const_get("Person").new("Frank")

const_get takes only a simple constant name, not a qualified name.


irb(main):247:0> (module Master
                     (class Person
                         (def initialize(name)
                             @name=name
                             end)
                         end)
                     end)
nil
irb(main):254:0> frank = Object.const_get("Master").const_get("Person").new("Frank")
#<Master::Person:0x3465ac @name="Frank">



> I would assume that the OP receives the full qualified name as a
> String and wants to get the class from there which can only be
> achieved with any of the other solutions shown.

Obviously, he wants to replace the literals by variables.


-- 
__Pascal Bourguignon__