-- (ID, on_success, on_failure)
PPI.OnLoad("7c08e2961c5e20e5bdbf7fc5", function(atcp)
  atcp.Listen("Room.Brief", OnRoomBrief)
end, function(reason)
  -- Optional callback for if it's not available.
end)

function OnPluginListChanged()
  PPI.Refresh()
end

  -- Prepare the arguments
  send_params({func_id, ...})
  
  -- Call the plugin
  local curr_caller = PPI.CallerID
  CallPlugin(id, invoke_msg, myID)
  PPI.CallerID = curr_caller
  
  -- Gather the return values
  local returns = receive_params(id)

  if not func then
    return
  end
  
  -- Call method, get return values
  PPI.CallerID = id
  local returns = {func(unpack(params))}
  PPI.CallerID = nil
  
  -- Send returns
  send_params(returns)

Dim myppi

Sub OnPluginListChanged()
  Set myppi = PPI.Load("7c08e2961c5e20e5bdbf7fc5")
  
  ' If we had an error, the PPI couldn't be loaded.
  If TypeName(myppi) = "PPI_Error" Then
    Note("The PPI couldn't be loaded: " & myppi.Error)
    Set myppi = Nothing
    Exit Sub
  ElseIf ATCP.Reloaded Then
    Note(myppi("somevar"))
    Note(Join(myppi("somearray").ToArray(), vbCrLf))
  End If
End Sub

PPI.Expose "foo", 42
PPI.Expose "bar", "test"
PPI.Expose "baz", array(1, "two", 3.5, array(10, 42))

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE script>

<script><![CDATA[

' used in the PPI base class
Class PPI_Error
  Public Error
End Class

' in progress
Class PPI_Method_Class
  Public Default Function Invoke(aParams)
    Note(Join(aParams))
    Invoke = array()
  End Function
End Class


Class PPI_List_Item
  Public Key
  Public Value
End Class

Class PPI_List
  Private aEntries()
  Private numEntries
  
  Private Sub Class_Initialize()
    numEntries = 0
  End Sub
  
  Public Function GetEntry(vKey)
    Set GetEntry = Nothing
    
    ' Array keys should not be compared
    If IsArray(vKey) Then
      Exit Function
    End If
    
    If numEntries < 1 Then
      Exit Function
    End If
    
    Dim i, entry
    For i = 0 To numEntries - 1
      Set entry = aEntries(i)
      If Not entry Is Nothing Then
        If (IsObject(vKey) And IsObject(entry.Key)) Then
          If vKey Is entry.Key Then
            Set GetEntry = entry
            Exit Function
          End If
        ElseIf (Not IsObject(vKey)) And (Not IsObject(entry.Key)) Then
          If entry.Key = vKey Then
            Set GetEntry = entry
            Exit Function
          End If
        End If
      End If
    Next
  End Function
  
  Public Sub SetEntry(vKey, vValue)
    ' Get the element by key
    Dim entry
    Set entry = GetEntry(vKey)
    
    ' If it doesn't exist yet, insert a new one
    If entry Is Nothing And Not IsEmpty(vValue) Then
      Set entry = New PPI_List_Item
      
      ' Check if there are any Empty elements
      Dim i
      For i = 0 To numEntries - 1
        If IsEmpty(aEntries(i)) Then
          Set aEntries(i) = entry
          Exit For
        End If
      Next
      
      ' As a last resort, resize the array and add a new entry.
      If i = numEntries Then
        ReDim Preserve aEntries(numEntries)
        Set aEntries(numEntries) = entry
        numEntries = numEntries + 1
      End If  
    End If
    
    ' If there was one, modify it and return
    If Not entry Is Nothing Then
      ' If the value is Empty, just remove the entry
      If IsEmpty(vValue) Then
        Set aEntries(vKey) = Nothing
      Else
        If IsObject(vKey) Then
          Set entry.Key = vKey
        Else
          entry.Key = vKey
        End If
        
        If IsObject(vValue) Then
          Set entry.Value = vValue
        Else
          entry.Value = vValue
        End If
      End If
    End If
  End Sub
  
  Public Property Get At(vKey)
    Dim entry
    Set entry = GetEntry(vKey)
    If Not entry Is Nothing Then
      If IsObject(entry.Value) Then
        Set At = entry.Value
      Else
        At = entry.Value
      End If
    End If
  End Property
  
  Public Property Let At(vKey, vValue)
    SetEntry vKey, vValue
  End Property
  
  Public Property Set At(vKey, vValue)
    SetEntry vKey, vValue
  End Property
  
  Public Property Get Count
    Count = numEntries
  End Property
  
  Public Function ToArray()
    Dim aList(), entry
    ReDim aList(0)
    
    Dim i
    For i = 0 To numEntries
      Set entry = GetEntry(i)
      If entry Is Nothing Then
        Exit For
      End If
      
      If IsObject(entry.Value) Then
        Set aList(i) = entry.Value
      Else
        aList(i) = entry.Value
      End If
      
      ReDim Preserve aList(i+1)
    Next
    
    If i = 0 Then
      ToArray = array()
    Else
      ReDim Preserve aList(i-1)
      ToArray = aList
    End If
  End Function
  
  Public Function ToMap()
    If numEntries < 0 Then
      ToMap = array()
    Else
      ToMap = aEntries
    End If
  End Function
  
  Public Sub MergeArray(aItems)
    Dim i
    For i = 0 To UBound(aItems)
      SetEntry i, aItems(i)
    Next
  End Sub
End Class


Class PPI_Translate_Class
  Private listCache
  
  ' Takes a PPI_List of items and serializes them.
  Private Function Serialize_Inner(listItems, listSerialized)
    ' If we already serialized it, don't do it again
    Set Serialize_Inner = listCache.GetEntry(listItems)
    If Not Serialize_Inner Is Nothing Then
      Serialize_Inner = Serialize_Inner.Value
      Exit Function
    End If
    Serialize_Inner = listCache.Count + 1
    listCache.At(listItems) = Serialize_Inner
    
    Dim ary_id
    ary_id = "PPIarray" & Serialize_Inner
    ArrayCreate ary_id
    
    ' Convert arrays to PPI_List-style maps
    If IsArray(listItems) Then
      Dim tempList
      Set tempList = New PPI_List
      tempList.MergeArray(listItems)
      Set listItems = tempList
      Set tempList = Nothing
    End If
    listItems = listItems.ToMap()
    
    ' Go over every entry
    Dim sKey, sValue, entry
    For Each entry In listItems
      sKey = Null
      
      ' Skip invalid keys
      If Not IsObject(entry.Key) Then
        sKey = entry.Key
        If TypeName(sKey) = "String" Then
          sKey = "s:" & sKey
        ElseIf IsNumeric(sKey) Then
          sKey = "n:" & CStr(sKey + 1)
        Else
          sKey = Null
        End If
      End If
      
      If Not IsNull(sKey) Then
        sValue = "z:~"
        
        ' Default to PPI-nil on invalid values
        If Not IsObject(entry.Value) Then
          sValue = entry.Value
          
          If TypeName(sValue) = "String" Then
            sValue = "s:" & sValue
          ElseIf TypeName(sValue) = "Boolean" Then
            If sValue Then
              sValue = "b:1"
            Else
              sValue = "b:0"
            End If
          ElseIf IsNumeric(sValue) Then
            sValue = "n:" & CStr(sValue)
          ElseIf IsArray(sValue) Then
            sValue = "t:" & Serialize_Inner(sValue, listSerialized)
          End If
        ElseIf TypeName(entry.Value) = "PPI_List" Then
          sValue = "t:" & Serialize_Inner(entry.Value, listSerialized)
        End If
        
        ArraySet ary_id, sKey, sValue
      End If
    Next
    
    listSerialized.At(Serialize_Inner - 1) = ArrayExport(ary_id, "|")
    ArrayDelete ary_id
  End Function
  
  Private Function Deserialize_Inner(aItems, iIndex)
    ' If we already deserialized it, don't do it again!
    Set Deserialize_Inner = listCache.GetEntry(iIndex)
    If Not Deserialize_Inner Is Nothing Then
      If IsObject(Deserialize_Inner.Value) Then
        Set Deserialize_Inner = Deserialize_Inner.Value
      Else
        Deserialize_Inner = Deserialize_Inner.Value
      End If
      Exit Function
    End If
    Deserialize_Inner = Empty
    
    ' Used to break apart each entry
    Dim sType, sValue
    
    ' Stores the deserialized results
    Dim listResults
    Set listResults = New PPI_List
    ' Cache the result list
    Set listCache.At(iIndex) = listResults
    
    ' Import the line into an array
    ArrayCreate "PPIarray" & iIndex
    ArrayImport "PPIarray" & iIndex, aItems(iIndex), "|"
    
    Dim aKeys
    aKeys = ArrayListKeys("PPIarray" & iIndex)
    If Not IsEmpty(aKeys) Then
      ' Deserialize each item one by one
      Dim key, val
      For Each key In aKeys
        ' Keep the value for later
        val = ArrayGet("PPIarray" & iIndex, key)
        
        ' Check the keytype first
        sType = Left(key, 1)
        sValue = Right(key, Len(key) - 2)
        
        If sType = "n" Then
          key = CDbl(sValue) - 1
        ElseIf sType = "s" Then
          key = sValue
        Else
          key = Null
        End If
        
        ' If the keytype is valid, check the value
        If Not IsNull(key) Then
          ' Split into type and value
          sType = Left(val, 1)
          sValue = Right(val, Len(val) - 2)
          
          ' Deserialize by type identifier
          If sType = "s" Then
            listResults.At(key) = sValue
          ElseIf sType = "n" Then
            listResults.At(key) = CDbl(sValue)
          ElseIf sType = "b" Then
            If vValue = "1" Then
              listResults.At(key) = True
            Else
              listResults.At(key) = False
            End If
          ElseIf sType = "t" Then
            Set listResults.At(key) = Deserialize_Inner(aItems, CInt(sValue) - 1)
          Else
            listResults.At(key) = Empty
          End If
        End If
      Next
    End If
    
    ArrayDelete "PPIarray" & iIndex
    
    Set Deserialize_Inner = listResults
  End Function
  
  Public Function Serialize(listItems)
    Set listCache = New PPI_List
    Dim listSerialized
    Set listSerialized = New PPI_List
    
    Serialize_Inner listItems, listSerialized
    Serialize = listSerialized.ToArray()
    
    Set listCache = Nothing
    Set listSerialized = Nothing
  End Function
  
  Public Function Deserialize(aItems)
    Set listCache = New PPI_List
    
    Set Deserialize = Deserialize_Inner(aItems, 0)
    
    Set listCache = Nothing
  End Function
  
  Public Function GetParams(sPlugin)
    Dim aParams()
    Dim length
    length = 0
    
    Dim i
    Do While Not IsEmpty(GetPluginVariable(sPlugin, "PPIparams_" & length + 1))
      ReDim Preserve aParams(length)
      aParams(length) = GetPluginVariable(sPlugin, "PPIparams_" & length + 1)
      
      length = length + 1
    Loop
    
    If length = 0 Then
      ReDim aParams(0)
      aParams(0) = ""
    End If
    
    Set GetParams = PPI.Translate.Deserialize(aParams)
  End Function
  
  Public Sub SetParams(aParams)
    aParams = PPI.Translate.Serialize(aParams)
    
    Dim i
    For i = 0 To UBound(aParams)
      SetVariable "PPIparams_" & (i + 1), "" & aParams(i)
    Next
  End Sub
End Class


Class PPI_Accessor
  Public PluginID
  Public Reloaded
  
  Public Default Function Access(sKey)
    If Not PluginSupports(PluginID, "PPI_ACCESS") = 0 Then
      Access = Empty
      Exit Function
    End If
    
    PPI.Translate.SetParams array(sKey)
    
    CallPlugin PluginID, "PPI_ACCESS", GetPluginID()
    
    Set Access = PPI.Translate.GetParams(PluginID).GetEntry(0)
    If Access Is Nothing Then
      Access = Empty
    ElseIf IsObject(Access.Value) Then
      Set Access = Access.Value
    Else
      Access = Access.Value
    End If
    
    CallPlugin PluginID, "PPI_CLEANUP", ""
  End Function
End Class


Class PPI_Base
  Private aAccessors()
  Private listExposed
  Private myTranslate
  
  Private Sub Class_Initialize()
    Set myTranslate = New PPI_Translate_Class
    Set listExposed = New PPI_List
    
    ReDim aAccessors(0)
    aAccessors(0) = Null
  End Sub
  
  
  Public Property Get Translate()
    Set Translate = myTranslate
  End Property
  
  
  Private Sub AddAccessor(sPlugin, accessor)
    Dim length
    length = UBound(aAccessors) + 1
    
    ReDim Preserve aAccessors(length)
    aAccessors(length) = array(GetPluginID(), New PPI_Accessor)
  End Sub
  
  Private Function GetAccessor(sPlugin)
    Dim entry
    entry = Null
    
    Dim i
    For i = 1 to UBound(aAccessors)
      entry = aAccessors(i)
      If entry(0) = sPlugin Then
        Set GetAccessor = entry(1)
        Exit Function
      End If
    Next
    
    Set GetAccessor = Nothing
  End Function
  
  
  ' Load the PPI interface for a given plugin
  Public Function Load(sPlugin)
    ' Make sure the plugin is accessible
    If Not IsPluginInstalled(sPlugin) Then
      Set Load = New PPI_Error
      Load.Error = "not_installed"
      Exit Function
    ElseIf Not GetPluginInfo(sPlugin, 17) Then
      Set Load = New PPI_Error
      Load.Error = "not_enabled"
      Exit Function
    End If
    
    Dim accessor
    Set accessor = GetAccessor(sPlugin)

    ' Only create a new one if we haven't made one for it before
    If accessor Is Nothing Then
      Set accessor = New PPI_Accessor
      accessor.PluginID = sPlugin
      accessor.Reloaded = True
      AddAccessor sPlugin, accessor
    End If
    
    Set Load = accessor
  End Function
  
  Public Sub Expose(sName, vValue)
    If IsObject(vValue) Then
      Set listExposed.At(sName) = vValue
    Else
      listExposed.At(sName) = vValue
    End If
  End Sub
  
  
  Public Sub PPI_ACCESS(sPlugin)
    Dim item
    Set item = PPI.Translate.GetParams(sPlugin).GetEntry(0)
    Set item = listExposed.GetEntry(item.Value)
    
    CallPlugin PluginID, "PPI_CLEANUP", ""
    
    PPI.Translate.SetParams(array(item.Value))
  End Sub
  
  Public Sub PPI_INVOKE(sPlugin)
    ' To-do
  End Sub
  
  Public Sub PPI_CLEANUP(sPlugin)
    Dim i
    i = 1
    Do Until IsEmpty(GetVariable("PPIparams_" & i))
      DeleteVariable("PPIparams_" & i)
      i = i + 1
    Loop
  End Sub
End Class

' Create the incoming PPI message receivers
Sub PPI_INVOKE(sPlugin)
  PPI.PPI_INVOKE(sPlugin)
End Sub

Sub PPI_ACCESS(sPlugin)
  PPI.PPI_ACCESS sPlugin
End Sub

Sub PPI_CLEANUP(sPlugin)
  PPI.PPI_CLEANUP(sPlugin)
End Sub 


' The global PPI object
Dim PPI
Set PPI = New PPI_Base

]]></script>

function add (a, b)
  return a + b
end -- add

print (add (2, 3)) --> 5

function add (id, a, b)
  return a + b
end -- add

  
  -- Call method, get return values
  local _caller = id
  local returns = {func(unpack(params))}
  
  -- Send returns
  send_params(returns)
end