May 26, 2020, 01:06:14 AM

Author Topic: Registering a type method to a Lua VM?  (Read 645 times)

Offline NoNameHere

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  • Posts: 9
Registering a type method to a Lua VM?
« on: February 07, 2019, 12:50:53 PM »
I was wondering if it's possible to register a BlitzMax type method instead of a function to a Lua virtual machine.

Here is the code I'm trying:
Code: [Select]
Framework BRL.StandardIO
Import PUB.Lua

Local DataStruct:SomeDataStructure = New SomeDataStructure
DataStruct.Data = "Some super important data"

Local Lua:LuaContext = New LuaContext


Type SomeDataStructure
Field Data:String
End Type

Type LuaContext
Field LuaVM:Byte Ptr
Field DataStructure:SomeDataStructure

Method Init(DataStructArg:SomeDataStructure)
DataStructure = DataStructArg

LuaVM = luaL_newstate()

LuaAddFunction("LuaPrintSomeData", LuaPrintSomeData)
End Method

Method Execute(ScriptFilename:String)
luaL_loadfile(LuaVM, ScriptFilename)

' Debug code, provides stack traces in case of crash
lua_getfield(LuaVM, LUA_GLOBALSINDEX, "debug")
lua_getfield(LuaVM, -1, "traceback")
lua_remove(LuaVM, -2)

If lua_pcall(LuaVM, 1, -1, -1) <> 0
Print "Lua error: " + lua_tostring(LuaVM, -1)
lua_pop(LuaVM, 1)
End If
End Method

Method LuaAddFunction(FunctionName:String, FunctionPtr:Byte Ptr)
lua_register(LuaVM, FunctionName, FunctionPtr)
End Method

Method LuaPrintSomeData(LuaState:Byte Ptr)
Print DataStructure.Data
Return 0
End Method
End Type

On current BlitzMaxNG v0.99 it gives me the following error:
Code: [Select]
C:/.../.bmx/test.bmx.console.release.win32.x64.c: In function '__m_test_LuaContext_Init_TSomeDataStructure':
C:/.../.bmx/test.bmx.console.release.win32.x64.c:84:105: error: '_m_test_LuaContext_LuaPrintSomeData_pb' undeclared (first use in this function); did you mean '__m_test_LuaContext_LuaPrintSomeData_pb'?
  ((struct _m_test_LuaContext_obj*)o)->clas->m_LuaAddFunction_Spb((struct _m_test_LuaContext_obj*)o,&_s2,_m_test_LuaContext_LuaPrintSomeData_pb);

Checking the .c file, function beginning with the double underscore is indeed declared. I don't know much about the inner workings of BlitzMaxNG, but could that single-underscore difference be an error in the compiler?
Or doing that (Registering a type method to Lua) is not allowed?

Offline Derron

  • Hero Member
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  • Posts: 2972
Re: Registering a type method to a Lua VM?
« Reply #1 on: February 07, 2019, 03:10:16 PM »
Brl.maxlua might help.

Or check my lua stuff:
It shows how to expose methods and functions from BlitzMax to Lua.



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