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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Unfortunately the answer is it depends, and it’s probably not
supported in Alpha 7 </span><span style='font-size:11.0pt;font-family:Wingdings;
color:#1F497D'>L</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The depends part is how the module got there and it all revolves
around the design we’ve come up with for the hosting of multiple languages. We
have a global object per ScriptRuntime which is (currently) a ScriptScope.
That scope holds onto a bunch of name/value bindings (where a value could be
another nested ScriptScope) and this is the closest concept (in the DLR) we
have to a module. The idea then is that each language exposes the global
object via its own mechanism picking something that makes the most sense for
that language. IronPython is going to expose the global object via import much
like it exposes other modules and .NET namespaces. But that doesn’t mean
sys.modules goes away, or that sys.modules becomes the global object. Instead
what we’re currently planning on doing is having import fallback to the global
object just as it falls back to the namespaces today. (As I type this I realize
it does complicate this scenario – so I’ll ask if this sound crazy or like a
bad idea? Should we instead try to merge them and have sys.modules == global
object? That has its own potential quirks but they could be dealt with.)<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>So that gives two different locations where modules can be
published: Either in the global object or in sys.modules. Therefore how you
added the module effects how the module gets removed. If the user did “import
foo” and we pulled up a .py file it’ll end up being in sys.modules. If we
pulled up a .js file from the DLR then it’ll be in the global object.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Further complicating things is the fact that the global object
isn’t really implemented yet. There’s some remnants of the old cross-language
module support we had early on but that’s not really the global object. So for
now in Alpha 7 I think the answer is that you execute the code. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>There’s also one more future possibility: And that is that to
expose Python specific functionality we may need to have a PythonEngine class
or something that lets you do things that aren’t part of the least common
denominator. There accessing sys.modules would be a likely piece of
functionality to have.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
users-bounces@lists.ironpython.com [mailto:users-bounces@lists.ironpython.com] <b>On
Behalf Of </b>Curt Hagenlocher<br>
<b>Sent:</b> Friday, January 04, 2008 6:03 AM<br>
<b>To:</b> Discussion of IronPython<br>
<b>Subject:</b> [IronPython] Deleting a module from the host<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>In a previous alpha of IPY 2.0, I deleted modules by saying<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-family:"Courier New"'>PythonEngine.CurrentEngine.SystemState.modules.Remove(moduleName)</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>(which is almost a direct analog of "del
sys.modules[moduleName]").<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>What's the best approach in Alpha 7? And will this
change as IronPython continues to migrate to the DLR?<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>I suppose I could literally execute Python code to do what I
want, but it seems so inelegant...<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>--<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>Curt Hagenlocher<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><a href="mailto:curt@hagenlocher.org">curt@hagenlocher.org</a><o:p></o:p></p>
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