The PowerShell team has released the second CTP of PowerShell 2 and it’s got so much new stuff in it, that it’s honestly hard to know where to start, so this first post is just going to be a list of the things I find the most exciting.

STA Threading

You can run PowerShell in Single Threaded Apartment mode, which will let us create WPF/XAML and some neat UI tricks that we couldn’t do before.

Modules

Modules are … like classes. They export public functions, and can have private functions and variables… you basically import the functions into your runspace, so you can call them, and they can share data via variables and even other functions in the same module. This is really awesome, and will almost certainly improve a dozen or more of my scripts which I’ve been using as containers for sets of functions.

Events

PowerShell has support for events, including a whole set of cmdlets: Register-ObjectEvent, Register-PSEvent, Wait-PSEvent, Remove-PSEvent, Unregister-PSEvent, Get-PSEvent, New-PSEvent, Get-PSEventSubscriber which will, in many cases, seem extremely familiar to users of x0n’s PSEventing snapin.

Constrained Runspaces

I haven’t had a chance to test this out yet, but the word is that we can create constrained runspaces that limit access to commands, scripts, and language elements. I’m not sure if this lets you prevent access to part of the .Net framework, but it looks interesting in terms of running other peoples scripts.

Splatting Operator

When you’ve got an array, you can split it up and pass it to a function so each element in the array shows up as a separate argument to the function, so if you have a function foo can call a function bar and pass it all the arguments that get passed to foo, without needing to know what they are or how many there are. (in v1, you have to do things like this: iex "&'bar' $args" which just gets ugly).

Verbose, Warning and Debug streams

I haven’t figured out how to really do anything with this yet, but the release notes say that these streams now contain string messages, invocation information and even pipeline metadata like counts of how many times each command in a pipeline has been invoked — someone was just asking for this on the usenet newsgroup the other day …

[new] Add-Type

There’s no help for this cmdlet, but it’s primarily a wrapper around the .net compilers (CSharp, CSharpVersion3, VisualBasic, and JScript, by default). However, it can also replace all the [Reflection.Assembly]::Load* methods so you can save some typing. I’ve figured out a couple of uses so far, and both are really useful:


# This is equivalent to [Reflection.Assembly]::LoadWithPartialName("System.Web")
Add-Type -Assembly System.Web
# And this is equivalent to [Reflection.Assembly]::LoadFrom( (ls PsXmppClient.dll) )
Add-Type -Path PsXmppClient.dll

# And this syntax lets you compile your own C# code on the fly to create custom types
# So next time you needed to complete Scripting Games 2008 event 8, you could use this:
Add-Type @"
using System;
public struct Song {
   public String Artist;
   public String Name;
   public TimeSpan Length;

   public Song(string artist, string name, TimeSpan length)
   {
      Artist = artist;
      Name = name;
      Length = length;
   }
}
"@

 

Incidentally, there’s no help for Add-Type for some reason, but you can get basic information about how to use a cmdlet by running a command like this: (Get-Command Add-Type).Definition -replace "`n","`n`n" …