PowerShell can parse itself just fine

Get-AST.ps1

function Get-AST
{
  param(
    [Parameter(Mandatory,ValueFromPipeline)]
    [psobject[]]$InputObject
  )
  
  process{
    foreach($Script in $InputObject){
      $Tokens = $Errors = @()
      $AST = [System.Management.Automation.Language.Parser]::ParseInput($Script,[ref]$Tokens,[ref]$Errors)
      
      $AST | Add-Member -MemberType NoteProperty -Name Tokens -Value $Tokens
      $AST | Add-Member -MemberType NoteProperty -Name Errors -Value $Errors
      
      Write-Output $AST
    }
  }
}