无论被调用，都会执行 Powershell 函数

Question

I'm having trouble understanding how Powershell treats functions. In the following script all functions are called, even if I never actually call the main function. Does powershell not have a concept of call chain?

param([string]$directory)

[string]$global:sqlscript;
$global:types = @{
"double" = "DOUBLE PRECISION"; 
"int" = "INTEGER"; 
"QString" = "INTEGER";
"Ignored" = "1";
"Normal" = "2";
"Critical" = "3" }

function resultToSql($element)
{
  $global:sqlscript += ('"')
  $global:sqlscript += ($element.name + '" ')
  $global:sqlscript += ($global:types.Get_Item($element.type))
  $global:sqlscript += (',' + [Environment]::Newline)
  $global:sqlscript += ('"' + $element.name + "_metric_group" + " " + $global:types.Get_Item($element.metric_group.type))   
  $global:sqlscript += (',' + [Environment]::Newline)
}

function xmlToSql($source)
{
  Write-Host "Parsing...";
  $global:sqlscript += "CREATE TABLE IF NOT EXISTS " + '"' + $source.spec.task.ToLower() + '"'+ [Environment]::NewLine
  $global:sqlscript += '"' + "id" + '"' + " SERIAL NOT NULL" + [Environment]::NewLine

  foreach ($node in $source.spec.measure) {
      resultToSql $node
  }

  foreach ($m in $source.spec.error) {
    resultToSql $m
  }

  $global:sqlscript += '"' + "weighted_sum" + '" ' + $global:types.Get_Item("double") + [Environment]::Newline;
}

function main
{
  if ($directory -eq $null) { exit }
  else
  {
    $xmlfiles = Get-ChildItem -Path $directory -include *Spec.xml
    foreach ($xmlfile in $xmlfiles)
    {
        Write-Host "Filename:" $xmlfile;
        [xml]$spec = Get-Content $file;
        xmlToSql $spec; 
        Write-Host $script;
    }
  }
}

Answer 1

PowerShell cant magically detect changes to scripts, close the ISE and re-open it then run your script again. If that fails take the contents of your script paste it in the ISE and click the execute button, i just did that and main didnt run.

Answer 2

Unlike a C/C++/C# program, "you" need to call the Main function - at the bottom of this script. When you run the script above all it does is create the functions you've defined. It doesn't run any of them. You have to do that by calling them in the script and one of those calls has to be at the script level (outside any functions).

Answer 3

Remove the main function container so it resembles the code below:

  if ($directory -eq $null) { exit }
  else
  {
    $xmlfiles = Get-ChildItem -Path $directory -include *Spec.xml
    foreach ($xmlfile in $xmlfiles)
    {
        Write-Host "Filename:" $xmlfile;
        [xml]$spec = Get-Content $file;
        xmlToSql $spec; 
        Write-Host $script;
    }
  }

Powershell doesn't execute from Main like C#/C++. It executes what statements are first received outside functions. In this case above it will execute the if statement first as it appears outside the function box.