CODEWITHSUNDEEP
powershellpowershell-2.0powershell-3.0
user1745750
user1745750

Reputation:

Powershell 2.0 - extract parameters from script block

Is there a way to extract the parameter list of a script block from outside the script block in PS 2.0 ?

Say we have

$scriptb = { PARAM($test) }

In Powershell 3.0 we can do this 

$scriptb.Ast.ParamBlock.Parameters.Count == 1 #true

The Ast property however was included in powershel 3.0 so the above will not work in PS 2.0 https://msdn.microsoft.com/en-us/library/System.Management.Automation.ScriptBlock_properties%28v=vs.85%29.aspx

Do you know of a way to do this in PS 2.0 ?

Upvotes: 4

Views: 634

Answers (3)

user1745750
user1745750

Reputation:

It looks like I can do this

function Extract {
    PARAM([ScriptBlock] $sb)

    $sbContent = $sb.ToString()
    Invoke-Expression "function ____ { $sbContent }"

    $method = dir Function:\____

    return $method.Parameters 
}

$script = { PARAM($test1, $test2, $test3) }
$scriptParameters = Extract $script

Write-Host $scriptParameters['test1'].GetType()

It will return a list of System.Management.Automation.ParameterMetadata https://msdn.microsoft.com/en-us/library/system.management.automation.parametermetadata_members%28v=vs.85%29.aspx

I think there should be a better way. Until then I will use a variation of the above code.

Upvotes: 0

Avshalom
Avshalom

Reputation: 8889

What about this?

$Scriptb = {
PARAM($test,$new)
return $PSBoundParameters
}
&$Scriptb "hello" "Hello2"

Upvotes: 0

Roman Kuzmin
Roman Kuzmin

Reputation: 42033

Perhaps it is not a pretty solution but it gets the job done:

# some script block
$sb = {
    param($x, $y)
}

# make a function with the scriptblock
$function:GetParameters = $sb

# get parameters of the function
(Get-Command GetParameters -Type Function).Parameters

Output:

Key Value
--- -----
x   System.Management.Automation.ParameterMetadata
y   System.Management.Automation.ParameterMetadata

Upvotes: 1

Related Questions