Question

Background

this post explains how one can consume extension methods in Powershell

http://community.bartdesmet.net/blogs/bart/archive/2007/09/06/extension-methods-in-windows-powershell.aspx

Compare this to what someone does in C# – they add a ‘using SomeAssembly’ and all the extension methods are loaded.

My questions

Did this get simpler Powershell 2.0. And if so, what does one do to use extension methods in Powershell 2.0? I have checked the publically available documentation and installed the CTP and am not seeing anything that is helping.

Answer 1

It doesn’t get easier in V2, but there is an extension mechanism which you might not be aware of.

I believe that part of the problem is in PowerShell’s handling (or lack thereof) of generics.

Also, for extension methods to be applied, the typed collections would have to be enforced, which is difficult in PowerShell. PowerShell, as a dynamic language, supports building collections of various types and most collections are represented as arrays of Object. Extension methods require the parameters to be inferred from the collection type and then the predicate checked to be of the correct type.

If your concern is for some LINQ like functions, there are a number of cmdlets that provide the same functionality in working with object collections.

PowerShell’s extended type system allows you to add methods to various types by adding an xml file or modifying an existing one (creating a new one is the recommended path). Jeffrey Snover demonstrates doing this with adding a ScriptProperty to the Object class in this blog post.

It’s not quite the same, but it could get the job done.