Logging Variable Types

# create a new custom validation attribute named "LogVariableAttribute":
class IdentifyTypeAttribute  : System.Management.Automation.ValidateArgumentsAttribute
{
  
    
  # this gets called whenever a new value is assigned to the variable:

  [void]Validate([object]$value, [System.Management.Automation.EngineIntrinsics]$engineIntrinsics)
  {
    # get the global variable that logs all changes:
    [System.Management.Automation.PSVariable]$variable = Get-Variable "loggedTypes" -Scope global -ErrorAction Ignore
    # if the variable exists and does not contain an ArrayList, delete it:
    if ($variable -ne $null -and $variable.Value -isnot [System.Collections.ArrayList]) { $variable = $null }
    # if the variable does not exist, set up an empty new ArrayList:
    if ($variable -eq $null) { $variable = Set-Variable -Name "loggedTypes" -Value ([System.Collections.ArrayList]@()) -Scope global -PassThru }
    
    [string]$line = (Get-PSCallStack)[-1].Position.Text
    $pattern = '\$(\w{1,})'
    $match = [regex]::Match($line, $pattern)
    if ($match.success)
    {
      
      # log the type contained in the variable
      $null = $variable.Value.Add([PSCustomObject]@{
          # use the optional source name that can be defined by the attribute:
          Value = $value.GetType()
          Timestamp = Get-Date
          # use the callstack to find out where the assignment took place:
          Name = [regex]::Match($line, $pattern).Groups[1]
          Position = [regex]::Match($line, $pattern).Groups[1].Index + (Get-PSCallStack)[-1].Position.StartOffset
          Line = (Get-PSCallStack).ScriptLineNumber | Select-Object -Last 1
          Path = (Get-PSCallStack).ScriptName | Select-Object -Last 1
      })

    }
  }
}