|This article relies on references to primary sources. (January 2013)|
|Stable release||2.7.3 (Final) / July 6, 2012|
|Platform||.NET Framework, Mono|
|Type||Python Programming Language Implementation|
|License||Apache License, v2.0|
IronPython is an implementation of the Python programming language targeting the .NET Framework and Mono. Jim Hugunin created the project and actively contributed to it up until Version 1.0 which was released on September 5, 2006. Thereafter, it was maintained by a small team at Microsoft until the 2.7 Beta 1 release; Microsoft abandoned IronPython (and its sister project IronRuby) in late 2010, after which Hugunin left to work at Google. IronPython 2.0 was released on December 10, 2008.
IronPython is implemented on top of the Dynamic Language Runtime (DLR), a library running on top of the Common Language Infrastructure that provides dynamic typing and dynamic method dispatch, among other things, for dynamic languages. The DLR is part of the .NET Framework 4.0 and is also a part of trunk builds of Mono. The DLR can also be used as a library on older CLI implementations.
Status and roadmap 
Release 2.6, released on December 11, 2009, and updated on April 12, 2010, targets CPython 2.6. IronPython 2.6.1 versions is binary compatible only with .NET Framework 4.0. IronPython 2.6.1 must be compiled from sources to run on .NET Framework 3.5. Iron Python 2.6.2, released on October 21, 2010, is binary compatible with both .NET Framework 4.0 and .NET Framework 3.5.
Release 2.7 was released on March 12, 2011 and it targets CPython 2.7.
Release 2.7.1 was released on October 21, 2011 and it targets CPython 2.7.
Differences with CPython 
|This section requires expansion. (July 2012)|
There are some differences between the Python reference implementation (CPython) and IronPython. Some projects built on top of IronPython are known not to work under CPython. Conversely, CPython applications that depend on extensions to the language that are implemented in C (e.g. NumPy) are not compatible with IronPython, although a commercially-supported open source project to address this is underway.
<script>-tags. It is then also possible to modify embedded XAML markup.
The technology behind this is called Gestalt.
The same works for IronRuby.
Until version 0.6 IronPython was released under the Common Public License. Following recruitment of the project lead in August 2004, IronPython was made available as part of Microsoft's Shared Source initiative. This license is not OSI approved but the authors claim it meets the Open Source Definition. With the 2.0 alpha release the license was changed to the Microsoft Public License, which the Open Source Initiative has confirmed complies with their definition of open source. The latest versions are released under the Apache License 2.0.
Interface extensibility 
One of IronPython's key advantages is in its function as an extensibility layer to application frameworks written in a .NET language. It is relatively simple to integrate an IronPython interpreter into an existing .NET application framework. Once in place, downstream developers can use scripts written in IronPython that interact with .NET objects in the framework, thereby extending the functionality in the framework's interface, without having to change any of the framework's code base.
IronPython makes extensive use of reflection. When passed in a reference to a .NET object, it will automatically import the types and methods available to that object. This results in a highly intuitive experience when working with .NET objects from within an IronPython script.
The following IronPython script manipulates .NET Framework objects. This script can be supplied by a third-party client-side application developer and passed into the server-side framework through an interface. Note that neither the interface, nor the server-side code is modified to support the analytics required by the client application.
from BookService import BookDictionary booksWrittenByBookerPrizeWinners = [book.Title for book in BookDictionary.GetAllBooks() if "Booker Prize" in book.Author.MajorAwards]
In this case, assume that the .NET Framework implements a class, BookDictionary, in a module called BookService, and publishes an interface into which IronPython scripts can be sent and executed.
This script, when sent to that interface, will iterate over the entire list of books maintained by the framework, and pick out those written by Booker Prize-winning authors.
What's interesting is that the responsibility for writing the actual analytics reside with the client-side developer. The demands on the server-side developer are minimal, essentially just providing access to the data maintained by the server. This design pattern greatly simplifies the deployment and maintenance of complex application frameworks.
The following script uses the .NET Framework to create a simple Hello World message.
import clr clr.AddReference("System.Windows.Forms") from System.Windows.Forms import MessageBox MessageBox.Show("Hello World")
The performance characteristics of IronPython compared to CPython, the reference implementation of Python, depends on the exact benchmark used. IronPython performs worse than CPython on most of the PyStone benchmarks but better on other benchmarks.
See also 
- Boo, a language for the .NET Framework and Mono with Python-inspired syntax and features borrowed from C# and Ruby.
- Jython - an implementation of Python for the Java Virtual Machine.
- Unladen Swallow - An optimization branch of CPython supported by Google and intended to be fully compatible and significantly faster.
- pypy - a self-hosting interpreter for the Python programming language.
- Tao Framework
- "Jim Hugunin's blog: IronPython 1.0 released today!". 2006-09-05. Retrieved 2006-12-14.
- Gavin Clarke (October 22, 2010). "Microsoft cuts loose Iron languages". The Register. Retrieved April 5, 2012.
- "Release dates for ironpython". 2008-12-10. Retrieved 2009-01-25.
- "2.0.3". ironpython.codeplex.com. Retrieved 2010-10-16.
- "2.6". ironpython.codeplex.com. Retrieved 2010-10-16.
- "2.7". ironpython.codeplex.com. Retrieved 2011-03-12.
- "2.7.1". ironpython.codeplex.com. Retrieved 2011-12-30.
- "18.104.22.168". ironpython.codeplex.com. Retrieved 2012-03-24.
- "Differences between IronPython 1.0 and CPython 2.4.3". Microsoft. 2007-12-18. Retrieved 2008-02-09.
- Foord, Michael. "New Project: Implementing .NET Libraries in Pure Python". Retrieved 2008-02-09.
- Eby, Phillip. "Children of a Lesser Python". Retrieved 2008-07-09.
- "Ironclad". Retrieved 2008-07-09.
- IronPython in the web browser - IronPython.net
- "Original IronPython homepage". July 28, 2004. Retrieved 2007-05-13.
- "Shared Source License for IronPython". April 28, 2006. Retrieved 2007-05-13.
- "Microsoft permissive license". April 28, 2007. Retrieved 2007-05-13.
- "Using .NET objects from IronPython in Resolver One". Retrieved 2008-11-18.
- "IronPython Performance Report". Retrieved 2009-10-05.
- Official website
- IronPython on Codeplex
- IronPython in Action - first English book on IronPython with foreword by Jim Hugunin