From: Thomas Coopman <thomas.coopman@...>
Date: 2006-07-24T05:36:38+09:00
Subject: Re: get caller of method

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Thanks for the quick answer, I didn't think about do.

I think I understand your explanation but I don't completly understand what
eval does.
I checked the documentation but I still don't really get it, could you
explain it?

Thomas

On 7/23/06, Ashley Moran <work@ashleymoran.me.uk> wrote:
>
>
> On Jul 23, 2006, at 8:06 pm, thomas coopman wrote:
>
> > Hi,
> >
> > Does there exist a method to get the object or type of object that
> > calls this method?
> >
> > for example:
> >
> > class Foo
> >       do
> > end
> > class Bar
> >       do
> > end
> >
> > do
> >       if caller.kind_of?(Foo)
> >               puts "Foo"
> >       elsif caller.kind_of?(Bar)
> >               puts "Bar"
> >       end
> > end
> >
> > Thanks!
> >
>
> Thomas
>
> I'm assuming you meant something like:
>
>    class Foo
>      def do_stuff
>        do_something
>      end
>    end
>    class Bar
>      def do_stuff
>        do_something
>      end
>    end
>
>    def do_something
>      if caller.kind_of?(Foo)
>        puts "Foo"
>      elsif caller.kind_of?(Bar)
>        puts "Bar"
>      end
>    end
>
> since "do" is a reserved word in Ruby.
>
> In this case you can do the following:
>
> def do_something(b = binding)
>    case eval("self", b)
>      when Foo then "Called by Foo"
>      when Bar then "Bar told me to do it"
>    end
> end
>
> Then you get:
>    Foo.new.do_stuff
>    => "Called by Foo"
>
>    Bar.new.do_stuff
>    => "Bar told me to do it"
>
> Note however that it would be possible for a method to "lie" and pass
> in another binding when the method is called.  And also it won't work
> in this case:
>
>    class Foo
>      do_something
>    end
>
> because the calling object is an instance of Class, but you could use:
>
>    def do_something(b = binding)
>      case eval("self.name", b)
>        when "Foo" then "Called when building Foo"
>        when "Bar" then "Bar's creator told me to do it"
>      end
>    end
>
> and you get:
>    class Foo
>      do_something
>    end
>    => "Called when building Foo"
>
>
> Maybe there is a better way to do this but it's a starter for 10.
>
>
> Ashley
>
>


-- 
Thomas Coopman
Thomas.coopman@gmail.com

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