當你調用某個函數時，PowerShell會增加一次嵌套層次。當一個函數調用了另一個函數，或著腳本，也會增加嵌套層次。今天分享一個函數，它能告訴你的腳本嵌套的層次：

function Test-NestLevel{$i = 1$ok = $truedo{try{$test = Get-Variable -Name Host -Scope $i}catch{$ok = $false}$i++} While ($ok) $i}

當你調用的函數具有遞歸調用時，上面的函數非常有用，來看一個調用的示例:

function Test-Diving{param($Depth) if ($Depth -gt 10) { return } "Diving deeper to $Depth meters..." $currentDepth = Test-NestLevel"calculated depth: $currentDepth" Test-Diving -depth ($Depth+1)} Test-Diving -depth 1 

當你運行Test-Diving時，函數會調用自己10次。函數使用一個參數來控制嵌套層次，而Test-NestLevel負責返回確切的深度數。

注意這里有個區別：Test-NestLevel返回絕對的嵌套層次，參數會紀錄這個函數調用自己多少次。如果Test-Diving被嵌入到另外一個函數中，絕對深度和相對深度會不同。

PS C:/> Test-Diving -Depth 1diving deeper to 1 meters...calculated depth: 1diving deeper to 2 meters...calculated depth: 2diving deeper to 3 meters...calculated depth: 3diving deeper to 4 meters...calculated depth: 4diving deeper to 5 meters...calculated depth: 5diving deeper to 6 meters...calculated depth: 6diving deeper to 7 meters...calculated depth: 7diving deeper to 8 meters...calculated depth: 8diving deeper to 9 meters...calculated depth: 9diving deeper to 10 meters...calculated depth: 10 PS C:/> & { Test-Diving -Depth 1 }diving deeper to 1 meters...calculated depth: 2diving deeper to 2 meters...calculated depth: 3diving deeper to 3 meters...calculated depth: 4diving deeper to 4 meters...calculated depth: 5diving deeper to 5 meters...calculated depth: 6diving deeper to 6 meters...calculated depth: 7diving deeper to 7 meters...calculated depth: 8diving deeper to 8 meters...calculated depth: 9diving deeper to 9 meters...calculated depth: 10diving deeper to 10 meters...calculated depth: 11 PS C:/>

Test-NestLevel總會返回從當前代碼的作用域到全局作用域的嵌套深度。