[IronPython] How to nest ScriptScopes

[Seshadri Pillailokam Vijayaraghavan]

You can use C# extension methods<http://msdn.microsoft.com/en-us/library/bb383977.aspx> to copy the variables without cluttering up the code too much

Here's what the code would look like...

    internal static class Extensions{

        internal static void SetOuter(this ScriptScope scope, ScriptScope outerScope) {
            scope.SetVariable("outer", outerScope);
            foreach (string name in outerScope.VariableNames) {
                scope.SetVariable(name, outerScope.GetVariable(name));
            }
        }

        internal static ScriptScope GetOuter(this ScriptScope scope) {
            return scope.GetVariable<ScriptScope>("outer");
        }

    }

You can then invoke it like this : innerScope.SetOuter(outerScope);

Hope that helps
sesh
From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Marty Nelson
Sent: Friday, May 09, 2008 10:44 AM
To: Discussion of IronPython
Subject: Re: [IronPython] How to nest ScriptScopes

That seems to work, although I used inner to execute (see below).

[TestMethod]
public void TestMethod1()
{
    var outerscope = _env.CreateScope();
    var innerscope = _env.CreateScope();

    int outerInput = 3;
    int innerInput = 2;
    outerscope.SetVariable("value", outerInput);
    innerscope.SetVariable("outer", outerscope);
    innerscope.SetVariable("value", innerInput);

    _pe.CreateScriptSourceFromString("result = outer.value + value", SourceCodeKind.Statements)
        .Execute(innerscope);
    var result = innerscope.GetVariable<int>("result");
    Assert.AreEqual(outerInput + innerInput, result);

    object ignore;
    Assert.IsFalse(outerscope.TryGetVariable("result", out ignore));
}

I'd prefer not to have the dot notation (I know in my sample I had conflicting variable names, but I don't expect that to be the case.  It's more a layering of available variables) .  Is there some python function I could write that would go through the outerscope and create variables at the inner scope using the name?  Or I'm I making this harder than it needs to be?  See below, where I just copied the variables.

[TestMethod]
public void TestMethod2()
{
    var outerscope = _env.CreateScope();
    var innerscope = _env.CreateScope();

    int outerInput = 3;
    int innerInput = 2;
    outerscope.SetVariable("foo", outerInput);

    foreach (string name in outerscope.VariableNames)
    {
        innerscope.SetVariable(name, outerscope.GetVariable(name));
    }
    innerscope.SetVariable("bar", innerInput);

    _pe.CreateScriptSourceFromString("result = foo + bar", SourceCodeKind.Statements)
        .Execute(innerscope);
    var result = innerscope.GetVariable<int>("result");
    Assert.AreEqual(outerInput + innerInput, result);

    object ignore;
    Assert.IsFalse(outerscope.TryGetVariable("result", out ignore));
}

Also, what does "when you have a closure" mean?


________________________________
From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Dino Viehland
Sent: Friday, May 09, 2008 9:59 AM
To: Discussion of IronPython
Subject: Re: [IronPython] How to nest ScriptScopes

It's not really intended that you nest the scopes yourself - usually the scopes only get nested when you have a closure.  And then we'll burn references into the parent scopes tuple's directly so we might not even see nested variables (although in some cases we might due a full runtime lookup and see them).

Instead of nesting them can you have a ScriptScope that contains other ScriptScope's?  In other words your inner most level is just a collection of ScriptScope's which you publish under some well known name into the outer level.  Then users can dot through them:

outermost = new ScriptScope();
innermost = new ScriptScope();
innermost.SetVariable("somevalue", 3);
outermost.SetVariable("next", innermost);

then run in outermost.


From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Marty Nelson
Sent: Friday, May 09, 2008 9:52 AM
To: users at lists.ironpython.com
Subject: [IronPython] How to nest ScriptScopes

I've gone over the 2.0 B2 source code, but I'm not clear how I might create nested ScriptScopes using the API in C#

One of the tests in EngineTests.cs uses "from published_context_test import x" but this is only one variable, and I'd rather do it from the C# setup side anyway.

I noticed that Scope, which ScriptScope contains, has the ability to take a parent Scope, but I'm not clear how I would do this.  It seems not to be exposed via ScriptScope.

We are using IronPython as a script based extension mechanism for our C# application, my interest is to have a set of established scopes that I can populate with the variables of current application objects at the appropriate level for the current script.

Thanks,

Marty Nelson
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