From: Paul Brannan <paul@...>
Date: 2001-12-08T06:42:57+09:00
Subject: [ruby-talk:27863] Re: Method creation question

On Sat, Dec 08, 2001 at 05:40:06AM +0900, Bob Hutchison wrote:
> I'd like to write:
> 
>     class Foo
>         myAttr :bar
>     end
> 
> and have two accessor functions added to class Foo.

I know of no way to do it without an eval:

  class Module
    def myAttr(symbol)
      class_eval <<-END
        def #{symbol}
          puts "returning #{symbol}"
          @#{symbol}
        end
        def #{symbol}=(value)
          puts "setting #{symbol}"
          @#{symbol}=value
        end
      END
    end
  end

  class Foo
    myAttr :foo
  end
  f = Foo.new
  f.foo = 42 #=> setting foo
  f.foo      #=> returning foo

The reason you must use an eval is that there currently is no way to get
the name of the current function.  It should be possible to get this
using an extension; I think it's stored in ruby_frame->last_func?  Using
class_eval, though, is slower to create the methods, but faster to
execute them.

Paul