当你调用某个函数时，PowerShell会增加一次嵌套层次。当一个函数调用了另一个函数，或着脚本，也会增加嵌套层次。今天分享一个函数，它能告诉你的脚本嵌套的层次：
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function Test-NestLevel{$i = 1$ok = $truedo{try{$test = Get-Variable -Name Host -Scope $i}catch{$ok = $false}$i++} While ($ok) $i} |
当你调用的函数具有递归调用时，上面的函数非常有用，来看一个调用的示例:
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function Test-Diving{param($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 |
当你运行Test-Diving时，函数会调用自己10次。函数使用一个参数来控制嵌套层次，而Test-NestLevel负责返回确切的深度数。
注意这里有个区别：Test-NestLevel返回绝对的嵌套层次，参数会纪录这个函数调用自己多少次。如果Test-Diving被嵌入到另外一个函数中，绝对深度和相对深度会不同。
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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总会返回从当前代码的作用域到全局作用域的嵌套深度。
