PowerShell: Nesting Functions Inside Functions

Demo 1: calling a function from within another function

function A{
    Param($functionToCall)
    Write-Host "Calling function: $functionToCall"

    # Obtain the scripts from the externally parsed function
    $script=(Get-Item "function:$functionToCall").ScriptBlock

    # invoking external function
    [ScriptBlock]::Create($script).Invoke();

}

function B{
    Write-Host "Function B has been invoked"
}

A -functionToCall B

Sample Out

PS C:\Users\JustinBieber> A -functionToCall B
Calling function: B
Function B has been invoked

Demo 2: Passing function into another function, then invoke on a remote target as a Job (to enable simultaneous executions)

function pingDomain{
    ping google.com;
    }

function startJobOnRemoteComputer{
    param(
        $remoteComputer,
        $functionToCall    
        )
    
    Write-Host "Executing $functionToCall on $remoteComputer";
    $script=(Get-Item "function:$functionToCall").Definition

    do{
        $session = New-PSSession -ComputerName $remoteComputer
        write-host "Connecting to remote computer $remoteComputer..."
        sleep -seconds 1
        if ($session){write-host "Connected."}
        } until ($session.state -match "Opened")

    $job=invoke-command -Session $session -AsJob -ScriptBlock{
                                                param($functionToCall);
                                                [ScriptBlock]::Create($functionToCall).Invoke();
                                                } -args $script  

    write-host "$($job.Name) has been initiated on $remoteComputer"  
    return $job;    
    }

$job=startJobOnRemoteComputer -remoteComputer "SHERVER009" -functionToCall pingDomain

Receive-Job -Id -job.Id;