[Ironruby-core] ironruby hosting as scripting engine

Jimmy Schementi Jimmy.Schementi at microsoft.com
Fri Nov 6 19:48:04 EST 2009


Will "my_app_object" be accessible in the do_stuff method? I think not, since our scope variables are just local ruby variables, right? What he'd really want is to define a method called "my_app_object" on the Script class, so then his ".s" files can use "my_app_object" anywhere, like:

engine Execute(@"class Script
  def my_app_object
    # do whatever you need to get the app object

  <script1.s content>

But I still don't like wrapping the user script in a class like that. The preferred way would be to create an instance of script and call instance_eval with the contents of the script1.s file:


From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Tomas Matousek
Sent: Friday, November 06, 2009 4:09 PM
To: ironruby-core at rubyforge.org
Subject: Re: [Ironruby-core] ironruby hosting as scripting engine

A better way of exposing application objects to the scripts and vice versa is to use ScriptScope:

var engine = IronRuby.CreateEngine();
var scope = engine.CreateScope();
scope.SetVariable("my_app_object", new App());

my_app_object.declare 'version 1'

def do_stuff
", scope);

var execute = scope.GetVariable<Func<string>>("do_stuff");

Top level Ruby methods defined in the executed script are published to the scope so that the host can read it via GetVariable method. Also, Ruby methods are convertible to delegates, so you can get the variable as Func<string> and call the delegate later.


From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Dotan N.
Sent: Friday, November 06, 2009 1:54 PM
To: ironruby-core at rubyforge.org
Subject: Re: [Ironruby-core] ironruby hosting as scripting engine

Yep i also needed to support input output but it all goes through the "$script" variable back to the backing C# object. for now, it makes it easier to have events and debugging. all in all the end result is that i provide an "API" exposed through $script.

Thanks, I clearly overlooked that.
On Fri, Nov 6, 2009 at 11:16 PM, Jimmy Schementi <Jimmy.Schementi at microsoft.com<mailto:Jimmy.Schementi at microsoft.com>> wrote:
Your solution sounds fine. To answer you first question though: engine.Execute("class Script; end") will always give you nil; classes return nil when defined:

>>> class Foo
... end
=> nil

You'll have to do this to get the actual class object:

engine.Execute("class Script; end; Script")


From: ironruby-core-bounces at rubyforge.org<mailto:ironruby-core-bounces at rubyforge.org> [mailto:ironruby-core-bounces at rubyforge.org<mailto:ironruby-core-bounces at rubyforge.org>] On Behalf Of Dotan N.
Sent: Friday, November 06, 2009 11:17 AM
To: ironruby-core at rubyforge.org<mailto:ironruby-core at rubyforge.org>
Subject: [Ironruby-core] ironruby hosting as scripting engine

Hi guys sorry for the lengthy mail but i believe this is interesting since i've found a solution that someone else could use.

just had a session of trying to embed IR in my application.
I'm defining a user script which contains some initialization code and a special worker function 'execute'

this is the "user script":

script1.s --------------------------------------------------------
$script.declare "version 1"

def execute
   $script.report "success"

what i'm doing is setting "script" as a global variable that is a gateway to my application.
I've tried this way first:

wrapping script1.s with "class Script <scriopt1.s content> end"
and doing Engine.Execute on it.

I expected to get a RubyObject as a result, which is the Script class.

then with the RubyObject i would do ObjectOperations.Invoke("execute"); when ever i wish.

I had 2 problems:

1. the RubyObject was always null. any idea why?
2. I couldn't really define a global variable properly (i've used the $a = a trick from the forum)

eventually i've realized this solution:
1. set global variable via RubyContext.DefineGlobalVariable
2.  i run everything on my script scope and Execute script1.s directly given a ScriptScope
3. do InvokeMember on the ScriptScope itself

from googling i've noticed the solution changed a lot along time.
so what is the proper way to do it?


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