Mailman 3 November 2003 - Python.NET

RE: PythonNet python.exe crashes...
by Brian Lloyd Nov. 14, 2003

Nov. 14, 2003

> I just run it in a fresh Win2k3 install and it crashes. I tried running > python.exe demo/helloform.py first and it crashed then just decided to try > python.exe alone and that's a problem. Any idea what's up? mmm... I just tried on a w2k3 box, and what I got was: - startup from cygwin shell works ok - startup from cmd shell works ok - double-click on python.exe - crashes :( It doesn't do this on XP. I'll have to dig into this one. > Will this let me develop .net web applications in Python as I would in C#? > > I understand you are embedding Python, similar to me embedding Python for > use in Delphi applications. Would this work for web development or would I > have all sorts of wrappers for my Python code in a first class > language like > C# which might just be calling to execute the Python code? It doesn't allow you define types that are directly visible at compile-time to C#, etc., so you probably would have to implement some sort of "pass- through" to delegate to your Python code. It should be possible to come up with a generic dispatcher though, so you wouldn't necessarily have to write a lot of wrappers. Brian Lloyd brian(a)zope.com V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com

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CVS updates
by Brian Lloyd Nov. 14, 2003

Nov. 14, 2003

Hi all - For the intrepid, I've checked in a number of fixes to things that have come up on the list: - Events refactored, -= now works for internalcalls, events are no longer directly callable (use OnSomeEvent(...) instead) - Implicit assembly loading now uses the PYTHONPATH to find assemblies. This means you can just add to sys.path to use an assembly that doesn't live in appbase or the GAC - Fixed a dumb bug in constructor handling that could cause you to get an 'IntPtr.Zero' instance rather than an exception in some cases when instantiating an object (this was the root of Michael's Point subclassing problem) If any of these are holding you up, you can get the fixes from CVS. I'm going to try to make a b2 tonight if the baby holds off for one more day :) Brian Lloyd brian(a)zope.com V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com

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Python for .NET 1.0 beta 2 released
by Brian Lloyd Nov. 14, 2003

Nov. 14, 2003

Python for .NET 1.0 beta 2 has been released - you can download it from: http://www.zope.org/Members/Brian/PythonNet/ Python for .NET is a near-seamless integration of Python with the .NET common language runtime. For more details, see the README: http://www.zope.org/Members/Brian/PythonNet/README.html The beta 2 release fixes several issues found in beta 1: - It is now possible to import assemblies from any directory on the PYTHONPATH (sys.path), in addition to importing from the appbase and the GAC - A problem that prevented registration of event handlers from working for some kinds of objects has been fixed - Constructor invokation handled some error conditions incorrectly, leading to odd results when calling some constructors There is also now a mailing list for discussion, questions and issues related to Python for .NET at: pythondotnet(a)python.org. To subscribe to the mailing list or read the online archives, see: http://mail.python.org/mailman/listinfo/pythondotnet Brian Lloyd brian(a)zope.com V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com

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Bug report: beta2 crashes on Win98SE, dot Net 1.1
by Petri Savolainen Nov. 13, 2003

Nov. 13, 2003

Full pkg crashes when starting the interpreter and existing 2.3.2 distro when importing anything from CLR. "Application generated an exception that could not be handled". Regards, Petri

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Generating MSIL code
by Lawrence Oluyede Nov. 7, 2003

Nov. 7, 2003

First and foremost I want to thank Bryan Lloyd for his great effort of making something useful for Python guys on the .NET Framework. Now I gotta explain the subject. I think that the "dream" feature for a Python .NET implementation is generation of standard IL code (not only bridging). I mean something like the previous [1] effort made by Mark Hammond with his Python .NET implementation (I've talked to him by email months ago and he told me that he stopped working on it cause he was no longer an ActiveState employee and nobody financed him to continue working). Do you, Brian, ever thougth to do something like that? What do you think about that? Thanks in advance 1 - http://starship.python.net/crew/mhammond/dotnet/ -- Lawrence "Rhymes" Oluyede http://loluyede.blogspot.com

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Need some feedback on events...
by Brian Lloyd Nov. 5, 2003

Nov. 5, 2003

Hi all - Looking at fixing a problem with events, I'm realizing that my original plan has a big hole in it :( Here's the situation: the framework requires that an event be implemented by providing an add_SomeEvent and a remove_SomeEvent method. However, the actual storage and mechanisms used to call the delegates registered via those special methods are completely up to the implementor of a class. When you write, for example, a class with an event in C# using the MS tools, you get: - add_* and remove_* methods - a private internal field to hold the delegate You do *not* get an automagic method to fire the event, because the class implementor is supposed to provide this if it appropriate (but may choose not to). The current Python.NET event stuff expects this setup, and it allows you to treat the event as a callable object - when you call the event, it tries to call that internal delegate. The problem is that its wrong :) According to everything I can find, a class is supposed to provide an 'OnSomeEvent' method to fire an event if it is appropriate for client code to fire the events of the class explicitly. If a class does not provide an 'OnSomeEvent' method, then it is assumed that it is not appropriate for the event to be fired by a client (and there is in fact no reliable way for the client to even try, since the dispatching to subscribers is purely internal to the class and could be done in arbitrary ways). I'm tempted to remove the ability to call event objects directly from Python, as this would match the convention and what you'd have to do in C# or VB, etc. (you'd call the OnSomeEvent method instead). The alternative would have to be doing some kind of automagical thing where we'd try lookup up an OnXXX if the usual private event field wasn't there, but that seems nasty... thoughts? Brian Lloyd brian(a)zope.com V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com

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Subclassing a subclassed Form
by Gordon McKeown Nov. 5, 2003

Nov. 5, 2003

Hi I changed the calls to Assembly.LoadFile() to Assembly.LoadFrom() and the problem appears to be resolved. I'm a newcomer to .NET so I'm not sure whether the behaviour when Assembly.LoadFile() was used to load the Assemblies is correct or not... Regards Gordon --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.536 / Virus Database: 331 - Release Date: 03/11/2003

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python for .net list on gmane
by Godefroid Chapelle Nov. 5, 2003

Nov. 5, 2003

For those who may be interested, I subscribed this list to gmane.org as gmane.comp.python.dotnet IOW you can also read it with your newsgroup client. -- Godefroid Chapelle (aka __gotcha) http://bubblenet.be

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Subclassing a subclassed Form
by Gordon McKeown Nov. 4, 2003

Nov. 4, 2003

Hi If I create a new (Form) class using Visual Studio and then subclass it in Python then I get "TypeError: no method matches given arguments" when executing 'WinForms.Application.Run(self)'. The new Form instance is created OK and the following returns true: 'isinstance(form, System.Windows.Forms.Form)' The only differences from the working examples appear to be: 1. The parameter is an object subclassed from a class that is in turn subclassed from System.Windows.Forms.Form. (The intermediate class is written in C#). 2. The class I created is not in the GAC. It is loaded using 'Assembly.LoadFile("D:\\forecastdev\\net\\TestGraphs\\bin\\Debug\\TestGraphs .exe")' Has anybody any suggestions? Regards Gordon --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.532 / Virus Database: 326 - Release Date: 27/10/2003

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Re: [Python.NET] Opening a SqlClient.Connection object fails
by Felix McAllister Nov. 3, 2003

Nov. 3, 2003

Er, this is embarassing. I've used an ADO connection string instead of an ADO.NET one. Sorry. Felix. _________________________________________________________________ Tired of spam? Get advanced junk mail protection with MSN 8. http://join.msn.com/?page=features/junkmail

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