BlitzMax/Modules/Other/Lua Core

"Lua is an extension programming language designed to support general procedural programming with data description facilities. It also offers good support for object-oriented programming, functional programming, and data-driven programming. Lua is intended to be used as a powerful, light-weight scripting language for any program that needs one." (from "Lua 5.1 Reference Manual" by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar Celes)

This module provides a BlitzMax interface to the Lua main and auxiliary APIs. It is almost complete, the only functions missing are those with variable argument lists (which are not yet supported by BlitzMax).

The axe.lua package also contains the full Lua 5.1.4 distribution. The Lua source code is completely integrated into the module, additional DLLs (or shared libraries, resp.) are no longer required.

Lua Documentation

The Lua Reference Manual is part of this distribution and may be directly visited from here:

Additional information can be found on the Lua web site; the Lua wiki contains further material about this module and related packages.

Introduction

The following description is not meant as a tutorial, but may still help you to start Lua programming within BlitzMax. More API-related information can be found in the Lua Reference Manual

Setting up a Lua VM

Running Lua scripts always require the instantiation of at least one Lua VM:

local LuaState:byte ptr = luaL_newstate()

The result of this instantiation is a pointer to a structure which contains the full state of the new VM and has to be passed as the first argument to almost any other Lua API function.

It is now time to "open" the intrinsic Lua libraries (note: these libraries are part of axe.lua now, external DLLs or shared libraries are not necessary):

luaL_openlibs(LuaState)

Always initialize the Lua VM by opening its libraries unless you really know what you are doing!

Usually, creating a single Lua state is sufficient, even further (Lua) threads share the basic Lua state (and its associated environment).

Shutting down a Lua VM

At the end, it's always a good idea to shut down the Lua VM

lua_close(LuaState)

The Lua interpreter has now been terminated and its state variable is no longer valid.

Accessing Lua Globals

The code

lua_pushstring(LuaState, "BMXString")
lua_setglobal (LuaState, "luaglobal")

defines a global Lua variable (called luaglobal) which contains a string (namely "BMXString").

Registering BlitzMax Functions

In order to access BlitzMax features from within a Lua script, it is necessary to implement suitable BlitzMax functions and register them in the Lua VM.

Such BlitzMax functions typically look as follows:

function BMXName:int (LuaState:Byte Ptr)
   ...      ' handling of parameters passed from Lua (if required)
     ...    ' actual function body
   ...      ' passing results back to Lua (if required)
   return 0 ' number of values returned to Lua
 end function

Such a function is then registered using

lua_register(LuaState, "luaname", BMXName)

This command registers a BlitzMax function (called BMXName) with the (global) name luaname under Lua. Both names may be equal, but they do not have to.

Running Lua Scripts From Within BlitzMax

The code

local Result:int = luaL_loadString(LuaState,LuaScript)
 if (Result &lt;&gt; 0) then
   ' ERROR!!!
   lua_close(LuaState) ' just to be complete
   end
 end if

loads and compiles a (BlitzMax) string containing a LuaScript. The result (of compilation) is left on the (Lua) stack.

lua_getfield(LuaState, LUA_GLOBALSINDEX, "debug")' get global "debug"
 lua_getfield(LuaState, -1, "traceback")       ' get "debug.traceback"
 lua_remove (LuaState, -2)           ' remove "debug" table from stack

 Result = lua_pcall(LuaState,1,-1,-1)' use "debug.traceback" as err.hdlr
 if (Result &lt;&gt; 0) then
   ' ERROR
   lua_close(LuaState) ' just to be complete
   end
 end if

actually evaluates the previously loaded script. The initially mentioned Lua commands just prepare for proper error messages should the Lua script fail.

Functions

Lua_atpanic

Function lua_atpanic:Byte Ptr (lua_state:Byte Ptr, panicf:Int(ls:Byte Ptr)

Description: see Lua Reference Manual

Lua_call

Function lua_call (lua_state:Byte Ptr, nargs:Int, nresults:Int)

Description: see Lua Reference Manual

Lua_checkstack

Function lua_checkstack:Int (lua_state:Byte Ptr, extra:Int)

Description: see Lua Reference Manual

Lua_close

Function lua_close (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_concat

Function lua_concat (lua_state:Byte Ptr, n:Int)

Description: see Lua Reference Manual

Lua_cpcall

Function lua_cpcall:Int (lua_state:Byte Ptr, func:Int(ls:Byte Ptr)

Description: see Lua Reference Manual

Lua_createtable

Function lua_createtable (lua_state:Byte Ptr, narr:Int, nrec:Int)

Description: see Lua Reference Manual

Lua_dump

Function lua_dump:Int (lua_state:Byte Ptr, writer:Int(ls:Byte Ptr,p:Byte Ptr,sz:Int,ud:Byte Ptr)

Description: see Lua Reference Manual

Lua_equal

Function lua_equal:Int (lua_state:Byte Ptr, index1:Int, index2:Int)

Description: see Lua Reference Manual

Lua_error

Function lua_error:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_gc

Function lua_gc:Int (lua_state:Byte Ptr, what:Int, data:Int)

Description: see Lua Reference Manual

Lua_getallocf

Function lua_getallocf:Byte Ptr (lua_state:Byte Ptr, ud:Byte Ptr Ptr)

Description: see Lua Reference Manual

Lua_getfenv

Function lua_getfenv (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_getfield

Function lua_getfield (lua_state:Byte Ptr, index:Int, k$z)

Description: see Lua Reference Manual

Lua_gethook

Function lua_gethook:Byte Ptr (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_gethookcount

Function lua_gethookcount:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_gethookmask

Function lua_gethookmask:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_getinfo

Function lua_getinfo:Int (lua_state:Byte Ptr, what$z, ar:lua_Debug Ptr)

Description: see Lua Reference Manual

Lua_getlocal

Function lua_getlocal$z (lua_state:Byte Ptr, ar:lua_Debug Ptr, n:Int)

Description: see Lua Reference Manual

Lua_getmetatable

Function lua_getmetatable:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_getstack

Function lua_getstack:Int (lua_state:Byte Ptr, level:Int, ar:lua_Debug Ptr)

Description: see Lua Reference Manual

Lua_gettable

Function lua_gettable (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_gettop

Function lua_gettop:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_getupvalue

Function lua_getupvalue$z (lua_state:Byte Ptr, funcindex:Int, n:Int)

Description: see Lua Reference Manual

Lua_insert

Function lua_insert (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_iscfunction

Function lua_iscfunction:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isnumber

Function lua_isnumber:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isstring

Function lua_isstring:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isuserdata

Function lua_isuserdata:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_lessthan

Function lua_lessthan:Int (lua_state:Byte Ptr, index1:Int, index2:Int)

Description: see Lua Reference Manual

Lua_load

Function lua_load:Int (lua_state:Byte Ptr, reader:Byte Ptr(ls:Byte Ptr,data:Byte Ptr,sz:Int Ptr)

Description: see Lua Reference Manual

Lua_newstate

Function lua_newstate:Byte Ptr (f:Byte Ptr(ud:Byte Ptr, p:Byte Ptr, osize:Int, nsize:Int)

Description: see Lua Reference Manual

Lua_newthread

Function lua_newthread:Byte Ptr (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_newuserdata

Function lua_newuserdata:Byte Ptr (lua_state:Byte Ptr, size:Int)

Description: see Lua Reference Manual

Lua_next

Function lua_next:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_objlen

Function lua_objlen:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_pcall

Function lua_pcall:Int (lua_state:Byte Ptr, nargs:Int, nresults:Int, errfunc:Int)

Description: see Lua Reference Manual

Lua_pushboolean

Function lua_pushboolean (lua_state:Byte Ptr, b:Int)

Description: see Lua Reference Manual

Lua_pushcclosure

Function lua_pushcclosure (lua_state:Byte Ptr, fn:Int(ls:Byte Ptr)

Description: see Lua Reference Manual

Lua_pushinteger

Function lua_pushinteger (lua_state:Byte Ptr, n:Int)

Description: see Lua Reference Manual

Lua_pushlightuserdata

Function lua_pushlightuserdata (lua_state:Byte Ptr, p:Byte Ptr)

Description: see Lua Reference Manual

Lua_pushlstring

Function lua_pushlstring (lua_state:Byte Ptr, s:Byte Ptr, size:Int)

Description: see Lua Reference Manual

Lua_pushnil

Function lua_pushnil (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_pushnumber

Function lua_pushnumber (lua_state:Byte Ptr, n:Double)

Description: see Lua Reference Manual

Lua_pushstring

Function lua_pushstring (lua_state:Byte Ptr, s$z)

Description: see Lua Reference Manual

Lua_pushthread

Function lua_pushthread:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_pushvalue

Function lua_pushvalue (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_rawequal

Function lua_rawequal:Int (lua_state:Byte Ptr, index1:Int, index2:Int)

Description: see Lua Reference Manual

Lua_rawget

Function lua_rawget (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_rawgeti

Function lua_rawgeti (lua_state:Byte Ptr, index:Int, n:Int)

Description: see Lua Reference Manual

Lua_rawset

Function lua_rawset (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_rawseti

Function lua_rawseti (lua_state:Byte Ptr, index:Int, n:Int)

Description: see Lua Reference Manual

Lua_remove

Function lua_remove (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_replace

Function lua_replace (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_resume

Function lua_resume:Int (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

Lua_setallocf

Function lua_setallocf (lua_state:Byte Ptr, f:Byte Ptr(ud:Byte Ptr, p:Byte Ptr, osize:Int, nsize:Int)

Description: see Lua Reference Manual

Lua_setfenv

Function lua_setfenv:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_setfield

Function lua_setfield (lua_state:Byte Ptr, index:Int, k$z)

Description: see Lua Reference Manual

Lua_sethook

Function lua_sethook:Int (lua_state:Byte Ptr, f(ls:Byte Ptr,ar:lua_Debug Ptr)

Description: see Lua Reference Manual

Lua_setlocal

Function lua_setlocal$z (lua_state:Byte Ptr, ar:lua_Debug Ptr, n:Int)

Description: see Lua Reference Manual

Lua_setmetatable

Function lua_setmetatable:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_settable

Function lua_settable (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_settop

Function lua_settop (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_setupvalue

Function lua_setupvalue$z (lua_state:Byte Ptr, funcindex:Int, n:Int)

Description: see Lua Reference Manual

Lua_status

Function lua_status:Int (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_toboolean

Function lua_toboolean:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_tocfunction

Function lua_tocfunction:Byte Ptr (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_tointeger

Function lua_tointeger:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_tolstring

Function lua_tolstring:Byte Ptr (lua_state:Byte Ptr, index:Int, size:Int Ptr)

Description: see Lua Reference Manual

Lua_tonumber

Function lua_tonumber:Double (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_topointer

Function lua_topointer:Byte Ptr (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_tothread

Function lua_tothread:Byte Ptr (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_touserdata

Function lua_touserdata:Byte Ptr (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_type

Function lua_type:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_typename

Function lua_typename$z (lua_state:Byte Ptr, tp:Int)

Description: see Lua Reference Manual

Lua_xmove

Function lua_xmove (fromState:Byte Ptr, toState:Byte Ptr, n:Int)

Description: see Lua Reference Manual

Lua_yield

Function lua_yield:Int (lua_state:Byte Ptr, nresults:Int)

Description: see Lua Reference Manual

Lua_getglobal

Function lua_getglobal (lua_state:Byte Ptr, name:String)

Description: see Lua Reference Manual

Lua_isboolean

Function lua_isboolean:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isfunction

Function lua_isfunction:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_islightuserdata

Function lua_islightuserdata:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isnil

Function lua_isnil:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isnone

Function lua_isnone:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isnoneornil

Function lua_isnoneornil:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_istable

Function lua_istable:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_isthread

Function lua_isthread:Int (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

Lua_newtable

Function lua_newtable (lua_state:Byte Ptr)

Description: see Lua Reference Manual

Lua_pop

Function lua_pop (lua_state:Byte Ptr, n:Int)

Description: see Lua Reference Manual

Lua_pushcfunction

Function lua_pushcfunction (lua_state:Byte Ptr, fn:Int(ls:Byte Ptr)

Description: see Lua Reference Manual

Lua_register

Function lua_register (lua_state:Byte Ptr, name:String, f:Int(ls:Byte Ptr)

Description: see Lua Reference Manual

Lua_setglobal

Function lua_setglobal (lua_state:Byte Ptr, name:String)

Description: see Lua Reference Manual

Lua_tostring

Function lua_tostring:String (lua_state:Byte Ptr, index:Int)

Description: see Lua Reference Manual

LuaL_addlstring

Function luaL_addlstring (B:Byte Ptr, s:Byte Ptr, l:Int)

Description: see Lua Reference Manual

LuaL_addsize

Function luaL_addsize (B:Byte Ptr, size:Int)

Description: see Lua Reference Manual

LuaL_addstring

Function luaL_addstring (B:Byte Ptr, s$z)

Description: see Lua Reference Manual

LuaL_addvalue

Function luaL_addvalue (B:Byte Ptr)

Description: see Lua Reference Manual

LuaL_argerror

Function luaL_argerror:Int (lua_state:Byte Ptr, narg:Int, extramsg$z)

Description: see Lua Reference Manual

LuaL_buffinit

Function luaL_buffinit (lua_state:Byte Ptr, B:Byte Ptr)

Description: see Lua Reference Manual

LuaL_callmeta

Function luaL_callmeta:Int (lua_state:Byte Ptr, obj:Int, e$z)

Description: see Lua Reference Manual

LuaL_checkany

Function luaL_checkany (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_checkinteger

Function luaL_checkinteger:Int (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_checklstring

Function luaL_checklstring:Byte Ptr (lua_state:Byte Ptr, narg:Int, size:Int Ptr)

Description: see Lua Reference Manual

LuaL_checknumber

Function luaL_checknumber:Double (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_checkstack

Function luaL_checkstack (lua_state:Byte Ptr, sz:Int, msg$z)

Description: see Lua Reference Manual

LuaL_checktype

Function luaL_checktype (lua_state:Byte Ptr, narg:Int, t:Int)

Description: see Lua Reference Manual

LuaL_checkudata

Function luaL_checkudata:Byte Ptr (lua_state:Byte Ptr, narg:Int, tname$z)

Description: see Lua Reference Manual

LuaL_getmetafield

Function luaL_getmetafield:Int (lua_state:Byte Ptr, obj:Int, e$z)

Description: see Lua Reference Manual

LuaL_gsub

Function luaL_gsub$z (lua_state:Byte Ptr, s$z, p$z, r$z)

Description: see Lua Reference Manual

LuaL_loadbuffer

Function luaL_loadbuffer:Int (lua_state:Byte Ptr, buff:Byte Ptr, sz:Int, name$z)

Description: see Lua Reference Manual

LuaL_loadfile

Function luaL_loadfile:Int (lua_state:Byte Ptr, filename$z)

Description: see Lua Reference Manual

LuaL_loadstring

Function luaL_loadstring:Int (lua_state:Byte Ptr, s$z)

Description: see Lua Reference Manual

LuaL_newmetatable

Function luaL_newmetatable:Int (lua_state:Byte Ptr, tname$z)

Description: see Lua Reference Manual

LuaL_newstate

Function luaL_newstate:Byte Ptr ()

Description: see Lua Reference Manual

LuaL_openlibs

Function luaL_openlibs (lua_state:Byte Ptr)

Description: see Lua Reference Manual

LuaL_optinteger

Function luaL_optinteger:Int (lua_state:Byte Ptr, narg:Int, d:Int)

Description: see Lua Reference Manual

LuaL_optlstring

Function luaL_optlstring:Byte Ptr (lua_state:Byte Ptr, narg:Int, d$z, size:Int Ptr)

Description: see Lua Reference Manual

LuaL_optnumber

Function luaL_optnumber:Double (lua_state:Byte Ptr, narg:Int, d:Double)

Description: see Lua Reference Manual

LuaL_prepbuffer

Function luaL_prepbuffer:Byte Ptr (B:Byte Ptr)

Description: see Lua Reference Manual

LuaL_pushresult

Function luaL_pushresult (B:Byte Ptr)

Description: see Lua Reference Manual

LuaL_ref

Function luaL_ref:Int (lua_state:Byte Ptr, t:Int)

Description: see Lua Reference Manual

LuaL_register

Function luaL_register (lua_state:Byte Ptr, libname$z, l:lua_Reg Ptr)

Description: see Lua Reference Manual

LuaL_typerror

Function luaL_typerror:Int (lua_state:Byte Ptr, narg:Int, tname$z)

Description: see Lua Reference Manual

LuaL_unref

Function luaL_unref (lua_state:Byte Ptr, t:Int, ref:Int)

Description: see Lua Reference Manual

LuaL_where

Function luaL_where (lua_state:Byte Ptr, lvl:Int)

Description: see Lua Reference Manual

LuaL_addchar

Function luaL_addchar (B:Byte Ptr, c:String)

Description: see Lua Reference Manual

LuaL_argcheck

Function luaL_argcheck (lua_state:Byte Ptr, cond:Int, narg:Int, extramsg:String)

Description: see Lua Reference Manual

LuaL_checkint

Function luaL_checkint:Int (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_checklong

Function luaL_checklong:Long (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_checkstring

Function luaL_checkstring:String (lua_state:Byte Ptr, narg:Int)

Description: see Lua Reference Manual

LuaL_dofile

Function luaL_dofile:Int (lua_state:Byte Ptr, filename:String)

Description: see Lua Reference Manual

LuaL_dostring

Function luaL_dostring:Int (lua_state:Byte Ptr, str:String)

Description: see Lua Reference Manual

LuaL_getmetatable

Function luaL_getmetatable (lua_state:Byte Ptr, tname:String)

Description: see Lua Reference Manual

LuaL_optint

Function luaL_optint:Int (lua_state:Byte Ptr, narg:Int, d:Int)

Description: see Lua Reference Manual

LuaL_optlong

Function luaL_optlong:Long (lua_state:Byte Ptr, narg:Int, d:Long)

Description: see Lua Reference Manual

LuaL_optstring

Function luaL_optstring:String (lua_state:Byte Ptr, narg:Int, d:String)

Description: see Lua Reference Manual

LuaL_typename

Function luaL_typename:String (lua_state:Byte Ptr, idx:Int)

Description: see Lua Reference Manual