ExecutionContext without references IronRuby

Ruby IronRuby
1

Hi,

This might be a bit of a strange request, but is it possible to get
access to the ExecutionContext without actually referencing the
IronRuby assembly?

As a quick demo, I wrote the following code:

        ScriptRuntime runtime = IronRuby.CreateRuntime();
        engine = IronRuby.GetEngine(runtime);
        RubyExecutionContext ctx =

IronRuby.GetExecutionContext(engine);

        list = new List<string>();
        ctx.DefineGlobalVariable("customers", list);

Ideally, what I wanted to write was something more like but $customers
is always nil.

        scope = engine.CreateScope();
        scope.SetVariable("$customers", list);

I was hoping this would have had the same affect as the code above.

Is this by design, a limitation or a bug?

Thanks

Ben
Blog.BenHall.me.uk

2

This is by design. Ruby global variables are Ruby special feature, not
all languages have such thing.
You can however use the scope and completely avoid statically
referencing IronRuby assemblies:

var runtime = ScriptRuntime.Create();
var scope = runtime.CreateScope(“Ruby”);
scope.SetVariable(“customers”, list);
scope.Execute(“p customers”);

In this example, “customers” is a method call that hits method_missing.
The IronRuby’s implementation of method_missing looks into the scope if
run in a hosted environment.

Tomas

3

We might define some library method that will look-up the scope’s
variables explicitly to enable this scenario.
As a workaround, this should work:

string startingBlock = @"
$scope = self
p $scope.customers
";

string startingBlock = @"require ‘mscorlib’
def
customers.method_missing(methodname, *args)
puts methodname
if(methodname.to_s =~ /Bob/)
customers.add(methodname.to_s)
else
super
end
end
customers.Bob
";

4

Thanks for your reply. The fact “customers” calls method_missing is a
bit of a problem, as what happens if you call customers within the
method_missing block?

       scope = engine.CreateScope();
        scope.SetVariable("customers", list);

        string startingBlock = @"require 'mscorlib'
                                def

customers.method_missing(methodname, *args)
puts methodname
if(methodname.to_s =~ /Bob/)
customers.add(methodname.to_s)
else
super
end
end
customers.Bob
";
scope.Execute(startingBlock);

I was working based on Phil H.'s Monkey Patching example and seeing
what happened.
I put some code which checks to see if the methodname is itself, but
then I check exceptions saying add isn’t on NilClass, must be doing
something wrong in that scenario

Code I added to the method was:
if( methodname.to_s == ‘customers’)
self

Like I said, only playing around to see what happens but I can see
people possible wanting to do this.

On Tue, Jun 24, 2008 at 1:50 AM, Tomas M.

5

Sorry, pressed Ctrl+Enter before finished.
You can use global $scope.customers in your implementation of
method_missing to access customers.

Tomas