From: Paul Brannan <pbrannan@...>
Date: 2003-09-10T05:40:12+09:00
Subject: Re: ANN: MetaTags 1.0

On Tue, Sep 09, 2003 at 12:59:49PM +0900, Dave Thomas wrote:
>    class Caml
>      def Caml.from_string(str)
>        # .. check string format ..
>        self.new(str)   # or something similar
>      end
>    end
> 
>    def Caml(str)
>      Caml.from_string(str)
>    end

A side-effect of this is that once all classes have a from_string
singleton method and a to_s instance method, I can now write:

  class Object
    def lexical_to(klass)
      return klass.from_string(to_s())
    end
  end

which is similar to boost::lexical_cast in C++:

    template<typename Target, typename Source>
    Target lexical_cast(Source arg)
    {
        std::stringstream interpreter;
        Target result;
        interpreter << arg;
        interpreter >> result;
        return result;
    }

(the actual implementation has a bit more than this with error checking
and such).

Paul