PPI - A plugin communications script

local PPI = require("ppi")
OnPluginListChanged = function()
  local ppi = PPI.Load("7c08e2961c5e20e5bdbf7fc5")
  if not ppi then
    error("Dependency plugin not installed!")
  end
  
  ppi.SomeMethodHere(parameters, go, here)
end

local PPI = require("ppi")

local function SomeMethodHere(parameters, go, here)
  print(parameters, go, here)
end

PPI.Expose("SomeMethodHere", SomeMethodHere)

local PPI_list = setmetatable({}, {__mode = "k"})

-- Takes a table and returns all values at numeric indices.
-- Example:
--  Input: {1, 2, 3, "5", "7", "10"}
--  Returns: 1, 2, 3, "5", "7", "10"
local function ExplodeParams(tbl)
  local param = table.remove(tbl, 1)
  if #tbl > 0 then
    return param, ExplodeParams(tbl)
  else
    return param
  end
end

-- A 'thunk' is a delayed resolver function.
local function new_thunk(id, func_name)
  return function(...)
    local params = {...}
    
    -- Prepare the arguments
    for i=1,#params do
      SetVariable("param" .. i .. "_" .. id, tostring(params[i]))
    end
    
    -- Call the method
    SetVariable("method_" .. id, func_name)
    CallPlugin(id, "PPI_" .. id .. "_PPI", GetPluginID())
    
    -- Clean up the arguments
    for i=1,#params do
      DeleteVariable("param" .. i .. "_" .. id)
    end
    
    -- Gather the return values
    local returns = {}
    local i = 1
    while GetPluginVariable(id, "return" .. i .. "_" .. GetPluginID()) ~= nil do
      table.insert(returns, GetPluginVariable(id, "return" .. i .. "_" .. GetPluginID()))
      i = i + 1
    end
    
    -- Have the other plugin clean up the return values
    CallPlugin(id, "PPI_" .. id .. "_PPI_CLEAN", GetPluginID())
    
    return ExplodeParams(returns)
  end
end

-- If the requested function hasn't yet had a thunk created,
-- create a new thunk and return it.
local PPI_meta = {
  __index = function(tbl, idx)
    local thunk = new_thunk(PPI_list[tbl].id, idx)
    tbl[idx] = thunk
    return thunk
  end,
}

local PPI = {
  -- Used to retreive a PPI for a specified plugin.
  Load = function(plugin_id)
    if not IsPluginInstalled(plugin_id) then
      return false
    end
    
    local tbl = PPI_list[plugin_id]
    if not tbl then
      tbl = setmetatable({}, PPI_meta)
      PPI_list[tbl] = {id = plugin_id}
      PPI_list[plugin_id] = tbl
    end
    return tbl
  end,
  
  -- Used by a plugin to expose methods to other plugins
  -- through its own PPI.
  Expose = function(name, func)
    local myPPI = PPI_list[GetPluginID()]
    myPPI[name] = func
  end,
}

-- create a PPI for this plugin
myPPI = {}
PPI_list[myPPI] = {id = GetPluginID()}
PPI_list[GetPluginID()] = myPPI

-- PPI request resolver
_G["PPI_" .. GetPluginID() .. "_PPI"] = function(id)
  local myPPI = PPI_list[GetPluginID()]
  local myID = PPI_list[myPPI].id
  if not myPPI then
    return
  end
  
  local params = {}
  local i = 1
  while GetPluginVariable(id, "param" .. i .. "_" .. myID) ~= nil do
    table.insert(params, GetPluginVariable(id, "param" .. i .. "_" .. myID))
    i = i + 1
  end
  
  local func_name = GetPluginVariable(id, "method_" .. myID)
  local func = myPPI[func_name]
  if not func then
    return
  end
  
  local returns = {func(ExplodeParams(params))}
  for i=1, #returns do
    SetVariable("return" .. i .. "_" .. id, tostring(returns[i]))
  end
end

-- Return value cleaner
_G["PPI_" .. GetPluginID() .. "_PPI_CLEAN"] = function(id)
  local i = 1
  while GetVariable("return" .. i .. "_" .. id) ~= nil do
    DeleteVariable("return" .. i .. "_" .. id)
    i = i + 1
  end
end

return PPI

-- Takes a table and returns all values at numeric indices.
-- Example:
--  Input: {1, 2, 3, "5", "7", "10"}
--  Returns: 1, 2, 3, "5", "7", "10"
local function ExplodeParams(tbl)
  local param = table.remove(tbl, 1)
  if #tbl > 0 then
    return param, ExplodeParams(tbl)
  else
    return param
  end
end

 -- Used by a plugin to expose methods to other plugins
  -- through its own PPI.
  Expose = function (name)
    assert (type (_G [name]) == "function", "Function " .. name .. " does not exist.")
    PPI_list[GetPluginID()] [name] = _G [name]
  end,

PPI.Expose("SomeMethodHere", SomeMethodHere)

PPI.Expose "SomeMethodHere"

module (..., package.seeall)

require "serialize"

local PPI_list = {}

-- A 'thunk' is a delayed resolver function.
local function new_thunk(id, func_name)
  return function(...)
    
    -- Prepare the arguments
    SetVariable("params_" .. id, serialize.save_simple {...})
    
    -- Call the method
    SetVariable("method_" .. id, func_name)
    CallPlugin(id, "PPI_" .. id .. "_PPI", GetPluginID())
    
    -- Clean up the arguments
    DeleteVariable("params_" .. id)
    
    local returns = {}  -- table of returned values
    local r = GetPluginVariable(id, "returns_" .. GetPluginID())
    if r then 
      local f = assert (loadstring ("r = " .. r))  -- convert serialized data back
      setfenv (f, returns)  -- make sure we use the returns table as our destination
      f ()   -- put data back in table "r"
    end -- if
    
    -- Have the other plugin clean up the return values
    CallPlugin(id, "PPI_" .. id .. "_PPI_CLEAN", GetPluginID())
    
    return unpack (returns.r)
  end
end

-- If the requested function hasn't yet had a thunk created,
-- create a new thunk and return it.
local PPI_meta = {
  __index = function(tbl, idx)
    local thunk = new_thunk(PPI_list[tbl].id, idx)
    tbl[idx] = thunk
    return thunk
  end,
}

local PPI = {
  -- Used to retreive a PPI for a specified plugin.
  Load = function(plugin_id)
    if not IsPluginInstalled(plugin_id) then
      return false
    end
    
    local tbl = PPI_list[plugin_id]
    if not tbl then
      tbl = setmetatable({}, PPI_meta)
      PPI_list[tbl] = {id = plugin_id}
      PPI_list[plugin_id] = tbl
    end
    return tbl
  end,
  
  -- Used by a plugin to expose methods to other plugins
  -- through its own PPI.
  Expose = function (name)
    assert (type (_G [name]) == "function", "Function " .. name .. " does not exist.")
    PPI_list[GetPluginID()] [name] = _G [name]
  end,
}

-- create a PPI for this plugin
myPPI = {}
PPI_list[myPPI] = {id = GetPluginID()}
PPI_list[GetPluginID()] = myPPI

-- PPI request resolver
_G["PPI_" .. GetPluginID() .. "_PPI"] = function(id)
  local myPPI = PPI_list[GetPluginID()]
  local myID = PPI_list[myPPI].id
  if not myPPI then
    return
  end
  
  local params = {}  -- table of parameters
  local p = GetPluginVariable(id, "params_" .. myID)
  if p then 
    local f = assert (loadstring ("t = " .. p))  -- convert serialized data back
    setfenv (f, params)  -- make sure we use the params table as our destination
    f ()   -- put data back in table "t"
  end -- if
    
  local func_name = GetPluginVariable(id, "method_" .. myID)
  local func = myPPI[func_name]
  if not func then
    return
  end
  
  -- call target function, get return values, serialize back into variable
  SetVariable("returns_" .. id, serialize.save_simple {func(unpack (params.t))})

end -- PPI request resolver

-- Return value cleaner
_G["PPI_" .. GetPluginID() .. "_PPI_CLEAN"] = function(id)
  DeleteVariable("returns_" .. id)
end

return PPI

local PPI = require("ppi")

require "tprint"

function SomeMethodHere (...)
  tprint {...}  
  
  return 1, "x", false, { y = 88 }
end

PPI.Expose "SomeMethodHere"

local PPI = require("ppi")
OnPluginListChanged = function()
  ppi = PPI.Load("15783160bde378741f9652d1")
  if not ppi then
    error("Dependency plugin not installed!")
  end
  tprint {ppi.SomeMethodHere (42, "Nick", true, {a = "56"} )}
end

Client received:

1=42
2="Nick"
3=true
4:
  "a"="56"

Service replied:

1=1
2="x"
3=false
4:
  "y"=88

PPI.Expose("MyMethod", function()
    print("Hallos.")
  end
)

local PPI_list = {}

local myID = GetPluginID()
local myPPI = {}

local params_id  = function(id) return "PPIparams_" .. id  end
local method_id  = function(id) return "PPImethod_" .. id  end
local returns_id = function(id) return "PPIreturns_" .. id end

local request_id = function(id) return "PPI_" .. id .. "_REQUEST" end
local cleanup_id = function(id) return "PPI_" .. id .. "_CLEANUP" end


local function request(id, func_name, ...)
  -- Prepare the arguments
  local params = {...}
  
  ArrayCreate(params_id(id))
  
  for i=1,#params do
    ArraySet(params_id(id), tostring(i), tostring(params[i]))
  end

  SetVariable(params_id(id), ArrayExport(params_id(id), "|"))
  ArrayDelete(params_id(id))
  
  -- Call the method
  SetVariable(method_id(id), func_name)
  CallPlugin(id, request_id(id), myID)
  
  -- Clean up the arguments
  DeleteVariable(params_id(id))
  DeleteVariable(method_id(id))
  
  -- Gather the return values
  local returns = {}
  
  ArrayCreate(returns_id(id))
  ArrayImport(returns_id(id), GetPluginVariable(id, returns_id(myID)), "|")
  
  for k,v in pairs(ArrayList(returns_id(id))) do
    returns[tonumber(k)] = v
  end
  ArrayDelete(returns_id(id))
  
  -- Have the other plugin clean up its return values
  CallPlugin(id, cleanup_id(id), myID)
  
  return unpack(returns)
end

-- A 'thunk' is a delayed resolver function.
local function new_thunk(id, func_name)
  return function(...)
    return request(id, func_name, ...)
  end
end

-- If the requested function hasn't yet had a thunk created,
-- create a new thunk and return it.
local PPI_meta = {
  __index = function(tbl, idx)
    local thunk = new_thunk(PPI_list[tbl].id, idx)
    tbl[idx] = thunk
    return thunk
  end,
}

local PPI = {
  -- Used to retreive a PPI for a specified plugin.
  Load = function(plugin_id)
    if not IsPluginInstalled(plugin_id) then
      return false
    end
    
    local tbl = PPI_list[plugin_id]
    if not tbl then
      tbl = setmetatable({}, PPI_meta)
      PPI_list[tbl] = {id = plugin_id}
      PPI_list[plugin_id] = tbl
    end
    return tbl
  end,
  
  -- Used by a plugin to expose methods to other plugins
  -- through its own PPI.
  Expose = function(name, func)
    myPPI[name] = (func and func or _G[name])
  end,
}

-- PPI request resolver
_G[request_id(myID)] = function(id)
  ArrayCreate(params_id(id))
  ArrayImport(params_id(id), GetPluginVariable(id, params_id(myID)), "|")
  
  local params = {}
  for k,v in pairs(ArrayList(params_id(id))) do
    params[tonumber(k)] = v
  end
  ArrayDelete(params_id(id))
  
  local func_name = GetPluginVariable(id, method_id(myID))
  local func = myPPI[func_name]
  if not func then
    return
  end
  
  local returns = {func(unpack(params))}
  ArrayCreate(returns_id(id))
  
  for i=1,#returns do
    ArraySet(returns_id(id), tostring(i), tostring(returns[i]))
  end

  SetVariable(returns_id(id), ArrayExport(returns_id(id), "|"))
  ArrayDelete(returns_id(id))
end

-- Return value cleaner
_G[cleanup_id(myID)] = function(id)
  DeleteVariable(returns_id(id))
end

return PPI

--[[

Author:  	Twisol 
Date:  3rd January 2010

Amendments: Nick Gammon
Date: 8th January 2010

Example of use:

SERVICE

-- require PPI module
require "ppi"

-- exposed function
function SomeMethodHere (a, b, c, d)
  -- do something with a, b, c, d
  return 1, 2, 3, 4
end

-- notify PPI of this function
ppi.Expose "SomeMethodHere"


CLIENT

-- require PPI module
require "ppi"

-- resolve dependencies
function OnPluginListChanged ()
  
  -- get PPI entries for all exposed function in this plugin
  my_service = ppi.Load ("15783160bde378741f9652d1")  -- plugin ID of service plugin

  if not my_service then
    Note ("Dependency plugin not installed!")
  end
  
end -- OnPluginListChanged

-- later on in plugin ...

-- call SomeMethodHere in other plugin, passing various data types, getting results

if my_service then
  w, x, y, z = my_service.SomeMethodHere (42, "Nick", true, { a = 63, b = 22 } )
end -- if service installed

--]]

module (..., package.seeall)

require "serialize"

-- For any function in our PPI table, try to call that in the target plugin
local PPI_meta = {
  __index = function(tbl, idx)
    return function(...)
       
        -- Call the method in the target plugin
        local status = CallPlugin (tbl._id, "PPI_" .. idx .. "_PPI_", serialize.save_simple {...})
        
        -- explain a bit if we failed
        if status ~= error_code.eOK then
          ColourNote ("white", "red", "Error calling " .. idx .. " using PPI from " .. GetPluginName ())
          check (status)
        end -- if
        
        local returns = {}  -- table of returned values
        local r = GetPluginVariable(tbl._id, "PPI_returns_PPI_") or "{}"
        local f = assert (loadstring ("r = " .. r))  -- convert serialized data back
        setfenv (f, returns) () -- load the returned values into 'returns'
        
        return unpack (returns.r)
      end  -- generated function
    end,
}  -- end PPI_meta table

-- PPI request resolver
local function PPI_resolver (func) 
  return function (p)
    local params = {}  -- table of parameters
    local f = assert (loadstring ("t = " .. p))  -- convert serialized data back
    setfenv (f, params) ()  -- load the parameters into 'params'
    
    -- call target function, get return values, serialize back into variable
    SetVariable("PPI_returns_PPI_", serialize.save_simple {func(unpack (params.t))})
  end -- generated function
  
end -- PPI_resolver

-- EXPOSED FUNCTIONS

-- We "load" a plugin by checking it exists, and creating a table saving the
-- target plugin ID, and have a metatable which will handle function calls
function Load (plugin_id)
  if IsPluginInstalled (plugin_id) then
    return setmetatable ({ _id = plugin_id }, PPI_meta)
  end -- if plugin exists
end -- function Load 

-- Used by a plugin to expose methods to other plugins
-- Each exposed function will be added to global namespace as PPI_<name>_PPI_
function Expose (name, func)
  assert (type (func or _G [name]) == "function", "Function " .. name .. " does not exist.")
  _G ["PPI_" .. name .. "_PPI_"] = PPI_resolver (func or _G [name])
end -- function Expose

OnPluginListChanged = function()
  local ppi = PPI.Load("7c08e2961c5e20e5bdbf7fc5")
  if not ppi then
    error("Dependency plugin not installed!")
  end
  
  ppi.SomeMethodHere(parameters, go, here)
end

local __V_MAJOR, __V_MINOR, __V_PATCH = 1, 0, 1
local __VERSION = string.format("%d.%d.%d", __V_MAJOR, __V_MINOR, __V_PATCH)
 
local PPI_list = {}
 
local myID = GetPluginID()
local myPPI = {}
 
local array_id   = function(id)      return "PPIarray_" .. id   end
local params_id  = function(id)      return "PPIparams_" .. id  end
local method_id  = function(id)      return "PPImethod_" .. id  end
 
local request_id = function(id) return "PPI_" .. id .. "_REQUEST" end
local cleanup_id = function(id) return "PPI_" .. id .. "_CLEANUP" end
 
 
function serialize(params, params_list)
  if not params_list then
    local params_list = {}
    serialize(params, params_list)
   
    local list = {}
    for k,v in ipairs(params_list) do
      list[k] = v
    end
    return list
  end
 
  if params_list[params] then
    return params_list[params]
  end
 
  local index = #params_list + 1
  params_list[params] = index
  params_list[index] = true
 
  local id = array_id(index)
  ArrayCreate(id)
 
  for k,v in pairs(params) do
    local key = nil
    if type(k) == "string" then
      key = "s:" .. k
    elseif type(k) == "number" then
      key = "n:" .. k
    end
   
    if key then
      local value = "z:~"
     
      if type(v) == "string" then
        value = "s:" .. v
      elseif type(v) == "number" then
        value = "n:" .. v
      elseif type(v) == "boolean" then
        value = "b:" .. (v and "1" or "0")
      elseif type(v) == "table" then
        value = "t:" .. serialize(v, params_list)
      end
     
      ArraySet(id, key, value)
    end
  end
 
  params_list[index] = ArrayExport(id, "|")
  ArrayDelete(id)
 
  return index
end
 
function deserialize(data_list, index, state)
  if not index or not state then
    return deserialize(data_list, 1, {})
  end
 
  if state[index] then
    return state[index]
  end
 
  local tbl = {}
  state[index] = tbl
 
  local id = array_id(index)
  ArrayCreate(id)
  ArrayImport(id, data_list[index], "|")
 
  for k,v in pairs(ArrayList(id)) do
    local key_type = k:sub(1,1)
    local key = nil
   
    if key_type == "s" then
      key = k:sub(3)
    elseif key_type == "n" then
      key = tonumber(k:sub(3))
    end
   
    if key then
      local item_type = v:sub(1,1)
      local item = v:sub(3)
     
      if item_type == "s" then
        tbl[key] = item
      elseif item_type == "n" then
        tbl[key] = tonumber(item)
      elseif item_type == "b" then
        tbl[key] = ((item == "1") and true or false)
      elseif item_type == "t" then
        tbl[key] = deserialize(data_list, tonumber(item), state)
      else
        tbl[key] = nil
      end
    end
  end
 
  ArrayDelete(id)
 
  return tbl
end
 
local function request(id, func_name, ...)
  -- Prepare the arguments
  local params = {...}
  for k,v in ipairs(serialize(params)) do
    SetVariable(params_id(id) .. "_" .. k, v)
  end
 
  -- Call the method
  SetVariable(method_id(id), func_name)
  CallPlugin(id, request_id(id), myID)
 
  -- Clean up the arguments
  for i=1,#params do
    DeleteVariable(params_id(id) .. "_" .. i)
  end
  DeleteVariable(method_id(id))
 
  -- Gather the return values
  local returns = {}
  local i = 1
  while GetPluginVariable(id, params_id(myID) .. "_" .. i) do
    returns[i] = GetPluginVariable(id, params_id(myID) .. "_" .. i)
    i = i + 1
  end
  returns = deserialize(returns)
 
  -- Have the other plugin clean up its return values
  CallPlugin(id, cleanup_id(id), myID)
 
  return unpack(returns)
end
 
-- A 'thunk' is a delayed resolver function.
local function new_thunk(id, func_name)
  return function(...)
    return request(id, func_name, ...)
  end
end
 
-- If the requested function hasn't yet had a thunk created,
-- create a new thunk and return it.
local PPI_meta = {
  __index = function(tbl, idx)
    local thunk = new_thunk(PPI_list[tbl].id, idx)
    tbl[idx] = thunk
    return thunk
  end,
}
 
local PPI = {
  __V = __VERSION,
  __V_MAJOR = __V_MAJOR,
  __V_MINOR = __V_MINOR,
  __V_PATCH = __V_PATCH,
 
  -- Used to retreive a PPI for a specified plugin.
  Load = function(plugin_id)
    if not IsPluginInstalled(plugin_id) then
      return false
    end
   
    local tbl = PPI_list[plugin_id]
    if not tbl then
      tbl = setmetatable({}, PPI_meta)
      PPI_list[tbl] = {id = plugin_id}
      PPI_list[plugin_id] = tbl
    end
    return tbl
  end,
 
  -- Used by a plugin to expose methods to other plugins
  -- through its own PPI.
  Expose = function(name, func)
    myPPI[name] = (func and func or _G[name])
  end,
}
 
-- PPI request resolver
_G[request_id(myID)] = function(id)
  -- Get requested method
  local func = myPPI[GetPluginVariable(id, method_id(myID))]
  if not func then
    return
  end
 
  -- Deserialize parameters
  local params = {}
  local i = 1
  while GetPluginVariable(id, params_id(myID) .. "_" .. i) do
    params[i] = GetPluginVariable(id, params_id(myID) .. "_" .. i)
    i = i + 1
  end
  params = deserialize(params)
 
  -- Call method, return values
  local returns = {func(unpack(params))}
  for k,v in ipairs(serialize(returns)) do
    SetVariable(params_id(id) .. "_" .. k, v)
  end
end
 
-- Return value cleaner
_G[cleanup_id(myID)] = function(id)
  local i = 1
  while GetVariable(params_id(id) .. "_" .. i) do
    DeleteVariable(params_id(id) .. "_" .. i)
    i = i + 1
  end
end
 
return PPI

Run-time error
Plugin: ppi_test_client (called from world: SmaugFUSS)
Function/Sub: OnPluginListChanged called by Plugin ppi_test_client
Reason: Executing plugin ppi_test_client sub OnPluginListChanged
[string "Plugin"]:9: Dependency plugin not installed!
stack traceback:
        [C]: in function 'error'
        [string "Plugin"]:9: in function <[string "Plugin"]:3>
Error context in script:
   5 :   my_service = ppi.Load("15783160bde378741f9652d1")
   6 :   if my_service then
   7 :     tprint (my_service)
   8 :   else
   9*:     error("Dependency plugin not installed!")
  10 :   end
  11 :   
  12 : end
  13 : 

This plugin requires you to install: Twisols_Stats_Gather plugin.

This is available from: www.somewebsite.com

Please download and install that, and then try again.

EnablePlugin(GetPluginID (), false)

if my_service then
  my_service.DoSomethingHere (a, b, c)
end -- if plugin available

--[[

PLUGIN-to-PLUGIN-INTERFACE (PPI)

Author:  	Twisol 
Date:  3rd January 2010

Amendments: Nick Gammon
Date: 8th January 2010

Example of use:

SERVICE

-- require PPI module
require "ppi"

-- exposed function
function SomeMethodHere (a, b, c, d)
  -- do something with a, b, c, d
  return 1, 2, 3, 4
end

-- notify PPI of this function
ppi.Expose "SomeMethodHere"

-- Or, for anonymous functions:
ppi.Expose ("DoSomethingElse", function () print "hello" end)

CLIENT

-- require PPI module
require "ppi"

-- resolve dependencies
function OnPluginListChanged ()
  
  -- get PPI entries for all exposed function in this plugin
  my_service = ppi.Load ("15783160bde378741f9652d1")  -- plugin ID of service plugin

  if not my_service then
    Note ("Dependency plugin not installed!")
  end
  
end -- OnPluginListChanged

-- later on in plugin ...

-- call SomeMethodHere in other plugin, passing various data types, getting results

if my_service then
  w, x, y, z = my_service.SomeMethodHere (42, "Nick", true, { a = 63, b = 22 } )
end -- if service installed

NOTES
-----

ppi.Load returns a table with various values in it about the target plugin (see below
for what they are). For example, _name is the plugin name of the target plugin, and
_version is the version number of that plugin.

If ppi.Load returns no value (effectively, nil) then the target plugin was not installed.

Provided a non-nil result was returned, you can then call any exposed function in the 
target plugin. There is currently no mechanism for finding what functions are exposed, for
simplicity's sake. However it would be possible to make a service function that returned all
exposed functions. If service plugins evolve in functionality, checking the target plugin's
version (the _version variable) should suffice for making sure plugins are synchronized.

To avoid clashes in variable names, you cannot expose a function starting with an underscore.

Communication with the target plugin is by global variables set up by the Expose function, along
the lines of:

PPI_function_name_PPI_  (one for each exposed function)

Also:

PPI__returns__PPI_ is used for storing the returned values.

--]]

-- hide all except non-local variables
module (..., package.seeall)

-- for transferring variables
require "serialize"

-- PPI version
local V_MAJOR, V_MINOR, V_PATCH = 1, 1, 0
local VERSION = string.format ("%d.%d.%d", V_MAJOR, V_MINOR, V_PATCH)

-- called plugin uses this variable to store returned values
local RETURNED_VALUE_VARIABLE = "PPI__returns__PPI_"

-- For any function in our PPI table, try to call that in the target plugin
local PPI_meta = {
  __index = function (tbl, idx)
    if (idx:sub (1, 1) ~= "_") then
      return function(...)
          -- Call the method in the target plugin
          local status = CallPlugin (tbl._id, "PPI_" .. idx .. "_PPI_", serialize.save_simple {...})
          
          -- explain a bit if we failed
          if status ~= error_code.eOK then
            ColourNote ("white", "red", "Error calling " .. idx .. 
                        " in plugin " .. tbl._name .. 
                        " using PPI from " .. GetPluginName () ..
                        " (" .. error_desc [status] .. ")")
            check (status)
          end -- if
          
          -- call succeeded, get any returned values
          local returns = {}  -- table of returned values
          local s = GetPluginVariable(tbl._id, RETURNED_VALUE_VARIABLE) or "{}"
          local f = assert (loadstring ("t = " .. s))  -- convert serialized data back
          setfenv (f, returns) () -- load the returned values into 'returns'
          
          -- unpack returned values to caller
          return unpack (returns.t)
        end  -- generated function
      end -- not starting with underscore
    end  -- __index function
}  -- end PPI_meta table

-- PPI request resolver
local function PPI_resolver (func) 
  return function (s)  -- calling plugin serialized parameters into a single string argument
    local params = {}  -- table of parameters
    local f = assert (loadstring ("t = " .. s))  -- convert serialized data back
    setfenv (f, params) ()  -- load the parameters into 'params'
    
    -- call target function, get return values, serialize back into variable
    SetVariable(RETURNED_VALUE_VARIABLE, serialize.save_simple {func(unpack (params.t))})
  end -- generated function
  
end -- PPI_resolver

-- EXPOSED FUNCTIONS

-- We "load" a plugin by checking it exists, and creating a table saving the
-- target plugin ID etc., and have a metatable which will handle function calls
function Load (plugin_id)
  if IsPluginInstalled (plugin_id) then
    return setmetatable (
      { _id = plugin_id,   -- so we know which plugin to call
        _name = GetPluginInfo (plugin_id, 1),
        _author = GetPluginInfo (plugin_id, 2),
        _filename = GetPluginInfo (plugin_id, 6),
        _enabled = GetPluginInfo (plugin_id, 17),
        _version = GetPluginInfo (plugin_id, 18),
        _required_version = GetPluginInfo (plugin_id, 19),
        _directory = GetPluginInfo (plugin_id, 20),
        _PPI_V_MAJOR = V_MAJOR,  -- version info
        _PPI_V_MINOR = V_MINOR,
        _PPI_V_PATCH = V_PATCH,
        _PPI_VERSION = VERSION,
       }, 
       PPI_meta)  -- everything except the above will generate functions
  else
    return nil, "Plugin ID " .. plugin_id .. " not installed"  -- in case you assert
  end -- if 
end -- function Load 

-- Used by a plugin to expose methods to other plugins
-- Each exposed function will be added to global namespace as PPI_<name>_PPI_
function Expose (name, func)
  assert (type (func or _G [name]) == "function", "Function " .. name .. " does not exist.")
  _G ["PPI_" .. name .. "_PPI_"] = PPI_resolver (func or _G [name])
end -- function Expose

static int ll_seeall (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  if (!lua_getmetatable(L, 1)) {
    lua_createtable(L, 0, 1); /* create new metatable */
    lua_pushvalue(L, -1);
    lua_setmetatable(L, 1);
  }
  lua_pushvalue(L, LUA_GLOBALSINDEX);
  lua_setfield(L, -2, "__index");  /* mt.__index = _G */
  return 0;
}

local myfile = [[
  module("test", package.seeall)
  function MYFOO()
    print("Hi.")
  end
]]

loadstring(myfile)()

"MYFOO"=function: 03083340
"_M":
  "MYFOO"=function: 03083340
  "_M"=table: 041A55A8
  "_NAME"="test"
  "_PACKAGE"=""
"_NAME"="test"
"_PACKAGE"=""

...
everything
...
"package":
    "preload":
    "loadlib"=function: 02F7A858
    "loaded":
      all other packages
      ...
      including this package
...

local script = [====[
--[[

<< put your function code here >>

]====]

local found = {}
local libs_used = {}

local funcs = {}
local libraries = {
      "string",
      "package",
      "os",
      "io",
      "bc",
      "progress",
      "bit",
      "rex",
      "utils",
      "table",
      "math",
      "debug",
      "coroutine",
      "lpeg",
      "sqlite3",
      "world",
  } -- end of libraries

local tables = {
      "trigger_flag",
      "alias_flag",
      "timer_flag",
      "custom_colour",
      "error_code",
      "sendto",
   }  -- end of tables

for k, v in pairs (_G) do
  if type (v) == "function" then
    funcs [k] = true
  end -- if 
end -- for

for _, lib in ipairs (libraries) do
  for k, v in pairs (_G [lib]) do
    if type (v) == "function" then
      funcs [lib .. "." .. k] = true
      if lib == "world" then
        funcs [k] = true
      end -- if
    end -- if 
  end -- for

end -- for each library

-- now do stuff like error_code, colours etc.

for _, lib in ipairs (tables) do
  for k, v in pairs (_G [lib]) do
      funcs [lib .. "." .. k] = true
  end -- for
end -- for each table

-- scan our script for matching functions

for w in string.gmatch (script, "[%a%d._]+") do
  if funcs [w] then
    local lib, func = string.match (w, "^([%a%d_]+)%.([%a%d_]+)")
    if lib then
      libs_used [lib] = libs_used [lib] or {}
      libs_used [lib] [func] = true
    else
      found [w] = true
    end -- if
  end -- if  

end -- for

local tl = {}
for k in pairs (libs_used) do
  table.insert (tl, k)
end -- for

table.sort (tl)

for _, lib in ipairs (tl) do
  print ("local", lib, "= {")
  for k in pairs (libs_used [lib]) do
    print ("  ", k, "=", lib .. "." .. k .. ",")
  end -- for
  print ("  }")
end -- for

local t = {}
for k in pairs (found) do
  table.insert (t, k)
end -- for

table.insert (t, "_G")

table.sort (t)

print ("local", table.concat (t, ", "), "=", table.concat (t, ", "))

-- hide all except non-local variables
module (...)

_G = nil

local _G = getfenv ()

-- hide all except non-local variables
module (..., package.seeall)

PPI.Expose("n_test", 42)
PPI.Expose("s_test", "blue")
PPI.Expose("b_test", true)
PPI.Expose("z_test", nil)
PPI.Expose("t_test", {
  "test",
  42,
  true,
  nil,
  function()
    print("test from ATCP")
    return {true, 42}
  end,
})

OnPluginListChanged = function()
  local atcp, reloaded = PPI.Load("7c08e2961c5e20e5bdbf7fc5")
  if not atcp then
    error("ATCP plugin not installed. Please install the ATCP plugin, then reinstall this plugin.")
  elseif reloaded then
    atcp.EnableModule("room_brief")
    _G["atcp"] = atcp
  end
end

local tstart = GetInfo(232)
for i=1,10000 do
  atcp.EnableModule('room_brief')
end

print(GetInfo(232) - tstart)

local tstart = GetInfo(232)
local EnableModule = atcp.EnableModule
for i=1,10000 do
  EnableModule('room_brief')
end

print(GetInfo(232) - tstart)

 
Time taken = 4.364 seconds  (test 1)
Time taken = 5.216 seconds  (test 2)

Time taken = 1.137 seconds  (test 1)
Time taken = 1.168 seconds  (test 2)

-- client
for i = 1, 10000 do
  my_service.SomeMethodHere (42, "Nick")
end -- for


-- service
function SomeMethodHere (...)
  return 1, 2
end

t1 = { 1, 2, 3, 4, 5 }
t2 = { 6, 7, t1 }

t1 = {}
t1 [1] = t1

t1 = { 
  wolf = { hp = 42, mana = 0 },
  naga = { hp = 100, mana = 10 }
  }

t1 = { 
  wolf = { hp = 42, mana = 0 },
  naga = { hp = 100, mana = 10 }
  }

twolf = {hp = 42, mana = 0}
tnaga = {hp = 100, mana = 10}
t1 = {wolf = twolf, naga = tnaga}

{
  naga = {
    hp = 100,
    mana = 10,
    },
  wolf = {
    hp = 42,
    mana = 0,
    },
  }

_G ["twolf"] = {hp = 42, mana = 0}
_G ["tnaga"] = {hp = 100, mana = 10}
t1 = {wolf = twolf, naga = tnaga}

local twolf = {hp = 42, mana = 0}
local tnaga = {hp = 100, mana = 10}
t1 = {wolf = twolf, naga = tnaga}
twolf = nil
tnaga = nil

t2 = {1, 2, 3}
t1 = {t2, t2}

{
  [1] = {
    [1] = 1,
    [2] = 2,
    [3] = 3,
    },
  [2] = {
    [1] = 1,
    [2] = 2,
    [3] = 3,
    },
  }

{
  [1] = 42,
  [2] = "nick",
  [3] = true,
  }

n:1|n:42|n:2|s:nick|n:3|b:1

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

function basefenv()
  local _G = getfenv(1)
  
  local _G2 = {
    __VERSION = _G.__VERSION,
    assert = _G.assert,
    collectgarbage = _G.collectgarbage,
    dofile = _G.dofile,
    error = _G.error,
    getfenv = _G.getfenv,
    getmetatable = _G.getmetatable,
    ipairs = _G.ipairs,
    load = _G.load,
    loadfile = _G.loadfile,
    loadstring = _G.loadstring,
    module = _G.module,
    next = _G.next,
    pairs = _G.pairs,
    pcall = _G.pcall,
    print = _G.print,
    rawequal = _G.rawequal,
    rawget = _G.rawget,
    rawset = _G.rawset,
    require = _G.require,
    select = _G.select,
    setfenv = _G.setfenv,
    setmetatable = _G.setmetatable,
    tonumber = _G.tonumber,
    tostring = _G.tostring,
    type = _G.type,
    unpack = _G.unpack,
    xpcall = _G.xpcall,
    
    bc = _G.bc,
    bit = _G.bit,
    coroutine = _G.coroutine,
    debug = _G.debug,
    io = _G.io,
    lpeg = _G.lpeg,
    math = _G.math,
    os = _G.os,
    package = _G.package,
    progress = _G.progress,
    rex = _G.rex,
    sqlite3 = _G.sqlite3,
    string = _G.string,
    table = _G.table,
    utils = _G.utils,
    world = _G.world,
    
    check = _G.check,
    gcinfo = _G.gcinfo,
    loadlib = _G.loadlib,
    
    alias_flag = _G.alias_flag,
    colour_names = _G.colour_names,
    custom_colour = _G.custom_colour,
    error_code = _G.error_code,
    error_desc = _G.error_desc,
    extended_colours = _G.extended_colours,
    sendto = _G.sendto,
    timer_flag = _G.timer_flag,
    trigger_flag = _G.trigger_flag
  }
  _G2._G = _G2
  
  return setmetatable(_G2, getmetatable(_G))
end

test = PPI.Load("7f88d638ba84f0c48b646dd2")

local tbl_param = {4}
test.FooBar(true, "2", 3, tbl_param, tbl_param)

_G.callbacks_list = {}

PPI.Expose("number", 42)
PPI.Expose("boolean", true)
PPI.Expose("string", "My Plugin")
PPI.Expose("table", {
  ["a key"] = "a value",
  [1] = 10,
  [2] = 50,
})
PPI.Expose("StoreCallback", 
  function(id, callback)
    table.insert(_G.callbacks_list, callback)
  end
)
PPI.Expose("ExecuteCallbacks",
  function(id, ...)
    for _,v in ipairs(_G.callbacks_list) do
      v(...)
    end
  end
)

test = PPI.Load("7f88d638ba84f0c48b646dd2")
require('tprint')

print("boolean: ", test.boolean)
print("string: ", test.string)
print("table:")
tprint(test.table)
print()
print("function: ", test.StoreCallback)

myfoo = 10

test.StoreCallback(function(id, ...) tprint{...} end)
test.StoreCallback(function(id, ...) print() print(myfoo, " - ", #{...}) end)
test.ExecuteCallbacks(10, 15, 30, "woohoo")

    local key = nil
    if type(k) == "string" then
      key = "s:" .. k
    elseif type(k) == "number" then
      key = "n:" .. k
    end

a = function() end
b = a
a = nil

{roomname}The Aylorian Temple of Ivar

tag roomname on

Welcome to Aardwolf MUD!
What be thy name, adventurer? tag roomname on
There is no player of the name "tag roomname on".

tag roomname off

PPI.Expose("foo",
  function(bar)
    -- baz
  end
)

PPI.Expose("foo",
  function(bar)
    -- baz
  end
)

function foo(bar)
  do_something_with_bar()
end
PPI.Expose("foo")

test = PPI.Load("my id")

a = function() print('1') end
PPI.Expose("a")
-- or alternatively, since you mentioned using debug.getinfo() to get the name
PPI.Expose(a)

b = test.a
a = function() print('2') end

b()

a = function() print('1') end
b = a
a = function() print('2') end
b()

t = {a = function() end}
tprint(debug.getinfo(t.a))

"nups"=0
"what"="Lua"
"func"=function: 03096DD8
"lastlinedefined"=1
"source"="Command line"
"currentline"=-1
"namewhat"=""
"linedefined"=1
"short_src"="[string "Command line"]"

function a()
  return 123
end
t = { myfunc = a }
send_to_plugin("bobs_plugin", t)

rift = {
  -- stuff cut out before
  display = function (spec)
    if spec then string.lower (spec) end
    spec = rift.long[spec] or spec
    AnsiNote (ansicolor (2), "Your rift contains:")
    for k, v in ipairs (rift.cats) do
      if (spec == v) or ((not spec) and rift.groups[v]) then
        AnsiNote (ansicolor (12), "\n" .. string.proper (rift.short[v] or v))
        rift.displaygroup (v)
      end -- if
    end -- for
    prompt.draw ()
    rift.min = nil
  end, -- func
  -- stuff cut out after
  }

dialog = plugin.GetWidget("dialog")

ok = dialog.GetChild("button_ok")
cancel = dialog.GetChild("button_cancel")

function ButtonOK()
  print("You clicked OK")
  dialog.Destroy()
end

function ButtonCancel()
  print("You clicked Cancel")
  dialog.Destroy()
end

ok.Bind("mouseup", ButtonOK)
cancel.Bind("mouseup", ButtonCancel)

function OnStartBattle ()
  DrawBorder "red"
end 

function OnStopBattle ()
  DrawBorder "black"
end 

-- call other plugin

battle_plugin.NotifyMeOfBattles (OnStartBattle, OnStopBattle)

function OnStartBattle ()
  DrawBorder "red"
end 

function OnStopBattle ()
  DrawBorder "black"
end 

-- call other plugin

ppi.Expose ("OnStartBattle")
ppi.Expose ("OnStopBattle")


battle_plugin.NotifyMeOfBattles ("OnStartBattle", "OnStopBattle")

function ButtonOK()
  print("You clicked OK")
  plugin.DestroyWidget("dialog")
end

plugin.BindEvent(plugin.GetWidget("dialog", "button_ok"), "mouseup", "ButtonOK")

function make_closure (f, colour)

return function ()
         f (colour)
       end -- inner function

end -- make_closure 

widgets = plugin.GetWidgetChildren("top_level_window")
for w in widgets:
  do_something_with_w()

my_object = { ... }
my_object.configuration = get_config() -- returns a table ref

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

<?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>

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))

  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)

  -- 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)

-- (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