From: "Iñaki Baz Castillo" <ibc@...>
Date: 2011-08-15T01:32:41+09:00
Subject: Re: How to use "case" to match class names? (=== not so funny)

2011/8/14 Chris White <cwprogram@live.com>:
> One way to potentially get around this is to have an object that simple holds a class and overrides the === operator to make case work properly:
>
> class ClassCheck
>  def initialize(klass)
>    @holder = klass
>  end
>
>  def ===(other)
>    @holder == other
>  end
> end
>
> klass = String
>
> case klass
>  when ClassCheck.new(String)
>    puts "String"
>  else
>    puts "Nothing"
> end
>
> You could also modify it to accept a variable number of arguments to check against multiple classes in a single when statement:
>
> class ClassCheck
>  def initialize(*klass)
>    @holder = klass
>  end
>
>  def ===(other)
>    @holder.each { | klass |
>      return true if klass == other
>    }
>    false
>  end
> end
>
> klass = String
>
> case klass
>  when ClassCheck.new(Object, Numeric, String)
>    puts "One of these"
>  else
>    puts "Nothing"
> end
>
> This form works with a single class as well.


Really great, thanks a lot.

-- 
Iñaki Baz Castillo
<ibc@aliax.net>