From: botp <botpena@...>
Date: 2008-12-10T10:04:49+09:00
Subject: Re: Given a string find the matching class

On Wed, Dec 10, 2008 at 6:06 AM, James Byrne <byrnejb@harte-lyne.ca> wrote:
> I have a situation where I desire to pass a string to a method that
> then:
> 1. Capitalizes the the string value
> 2. Finds a class by that name
> Something like:
> def findmyclass(m)
>  find_class_by_name(m.capitalize)
> end
> Is this possible (surely) and if so, how is it done?

1 class names are constants, thus
    1.1 they start w upcase, and
    1.2 are case sensitive

2 you get the value of a quoted/stringified constant
    by using const_get

3 you can then check the value returned  by checking if it #is_a? Class

eg,

> Object.const_get("XX").is_a? Class
=> true
> Object.const_get("Xx").is_a? Class
=> true
> Object.const_get("YY")
NameError: uninitialized constant YY

now,  if you want to find classes tucked in on other modules/classes,
you'll have to scan the whole ObjectSpace; eg, looking for a class
named "C" wc is in "A::B::C"...

eg,

> ObjectSpace.each_object(Class).each {|x| p x if x.name =~ /^M/ }
Method
MatchData
Module
M::MM