Re: [Ironruby-core] Why does attr_accessor create a property, but method is just a method?

[Curt Hagenlocher]

I believe this works as designed.

The problem is that Ruby doesn't otherwise distinguish syntactically between a 
property and a method with no parameters. Imagine that you're in tooling such 
as Visual Studio. By default, the values of properties are automatically 
displayed in the debugger and in tool tips. But if I happen to have a no-args 
method named format_cdrive, I probably don't want that code to be run just to 
inspect its value. Effectively, attr_accessor, attr_reader and attr_writer are 
used by IronRuby as signals that indicate this operation is free of 
potentially-nasty side effects.

From: ironruby-core-boun...@rubyforge.org 
[mailto:ironruby-core-boun...@rubyforge.org] On Behalf Of Brian Genisio
Sent: Thursday, July 22, 2010 5:49 AM
To: ironruby-core@rubyforge.org
Subject: Re: [Ironruby-core] Why does attr_accessor create a property, but 
method is just a method?

So, I haven't heard anything about this yet on Stack Overflow, or this list.

Does anyone know if this is this a bug in IronRuby interop?
Thanks,
Brian

On Wed, Jul 21, 2010 at 12:34 PM, Brian Genisio 
<briangeni...@gmail.com<mailto:briangeni...@gmail.com>> wrote:
This is a cross-post from Stack Overflow, but I haven't heard a peep there, so 
I figured I'd try here:

I am playing around with the interop between C# and IronRuby.  I have noticed 
that if I define a property in Ruby using `attr_accessor`, it is presented to 
C# as a property.  If, on the other hand, I create the exact same code 
manually, it comes back as a method.

For example, take this code:

    var engine = IronRuby.Ruby.CreateEngine();
    string script = @"
      class Test
        attr_accessor :automatic

        def manual
          @manual
        end

        def manual=(val)
          @manual = val
        end

        def initialize
          @automatic = ""testing""
          @manual = ""testing""
        end
      end

      Test.new
    ";
    var testObject = engine.Execute(script);

    var automatic = testObject.automatic;
    var manual = testObject.manual;

When you look at the C# `automatic` variable, the value is a string of 
"testing".  If you look at the C# `manual` variable, it is type 
IronRuby.Builtins.RubyMethod.

Ultimately, I want to create my own properties in Ruby that can be used in C#, 
but I can't seem to make them be visible as properties like `attr_accessor` 
does.

I THINK, that there is some magic going on in the Module code of the Ruby 
source code (ModuleOps.cs:DefineAccessor).  Is there any way to do this in Ruby 
code directly?

Thanks,
Brian


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