Demonstrates the scope pyramid for functions in Modules

poc-moduleScopeHierarchy.ps1

New-Module -Name Test -ScriptBlock {
	function Get-Test1
	{
		[CmdletBinding()]
		param ()
		
		$var = 24
		$depth = 0
		try
		{
			while ($variable = Get-Variable -Name var -Scope $depth -ErrorAction Ignore)
			{
				Write-Host ("  Depth: {0:D2} | Value: {1:D3} | Callstack: {2}" -f $depth, $variable.Value, (Get-PSCallStack).Count)
				$depth = $depth + 1
			}
		}
		catch { }
	}
	function Get-Test2
	{
		[CmdletBinding()]
		param (
			
		)
		
		$var = 12
		
		1 .. 3 | ForEach-Object {
			if ($_ -eq 1) { Get-Test1 }
		}
	}
	function Get-Test3
	{
		[CmdletBinding()]
		param (
			
		)
		
		$var = 7
		
		Get-ExternalTest -Mode 1
	}
	$script:var = 6
} | Import-Module
$var = 3

function Get-ExternalTest
{
	[CmdletBinding()]
	param (
		[ValidateSet('1', '2')]
		[int]
		$Mode = 1
	)
	
	$var = 42
	switch ($Mode)
	{
		1 { Get-Test1 }
		2 { Get-Test2 }
	}
}

Write-Host "Test: Calling Get-Test2" -ForegroundColor Green
Get-Test2
Write-Host "Test: Calling Get-Test1" -ForegroundColor Green
Get-Test1
Write-Host "Test: Calling Get-Test3" -ForegroundColor Green
Get-Test3

# This shows, that the $var in Get-ExternalTest is NOT seen in te scope tree
Write-Host "Test: Calling Get-ExternalTest -Mode 2" -ForegroundColor Green
Get-ExternalTest -Mode 2
Write-Host "Test: Calling Get-ExternalTest -Mode 1" -ForegroundColor Green
Get-ExternalTest -Mode 1

Note:

• Commands from other modules or no module at all are not part of the scope pyramid
• There is no direct correlation between scopes and callstack!

Scope pyramid from within a module:

Global > Module (script) > Internal Command 1 > Internal Command 2 > … Internal Command N

while calling commands outside of the module (such as ForEach-Object) may be part of the callstack, but are skipped in the scope pyramid