CODEWITHSUNDEEP
powershell
Matthew MacFarland
Matthew MacFarland

Reputation: 2741

How should I execute script block parameters in a PowerShell function?

If I create a PowerShell function with a parameter of type [scriptblock], which method is the best to execute the script block inside the function? And why?

I am aware of the following options:

Upvotes: 1

Views: 581

Answers (1)

Ansgar Wiechers
Ansgar Wiechers

Reputation: 200573

. runs the scriptblock in the current scope. & runs the scriptblock in a child scope (same as running the scripblock via its Invoke() method). Which one you want to use depends on the outcome you want to achieve.

Demonstration:

Running via Invoke() method:

PS C:\> $s = { $a = 2; $a }
PS C:\> $a = 1
PS C:\> $s.Invoke()
2
PS C:\> $a
1

Running via call operator:

PS C:\> $s = { $a = 2; $a }
PS C:\> $a = 1
PS C:\> & $s
2
PS C:\> $a
1

Running via dot-sourcing operator:

PS C:\> $s = { $a = 2; $a }
PS C:\> $a = 1
PS C:\> . $s
2
PS C:\> $a
2

If you need the scriptblock to modify something in the current scope: use the . operator. Otherwise use call operator or Invoke() method.

Do not use Invoke-Expression.

Upvotes: 5

Related Questions