Bi-directional C and Lua

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SoCoder -> Snippet Home -> Variables

HoboBen	Created : 12 January 2011 Edited : 12 January 2011 System : Cross Platform Language : Monkey Bi-directional C and Lua
Just the simplest of examples. A C host program runs a Lua script, gets and sets the script's variables, runs the script's functions, and provides a C function for the script to call. (Lua 5.1) bidirectional.lua FirstName = "Unset"; SecondName = "Unset"; ThirdName = "Unset"; LastName = "Unset"; ImportantNumber = 0; function Multiply(i, j) return (i * j); end function Test() HAPI_Print(FirstName, " ", SecondName, " ", ThirdName, " ", LastName, "\n"); ImportantNumber = 42; end --v bidirectional.c /* compile: gcc -llua bidirectional.c -o bidirectional / #include <stdlib.h> #include <stdio.h> #include <lua.h> #include <lauxlib.h> #include <lualib.h> / Host API / int HAPI_Print(lua_State pLuaState) { int i; int argc = lua_gettop(pLuaState); for (i = 1; i <= argc; i++) { printf(lua_tostring(pLuaState, i)); } return 0; } /* Client API / void CAPI_Test(lua_State pLuaState) { lua_getglobal(pLuaState, "Test"); lua_call(pLuaState, 0, 0); } double CAPI_Multiply(lua_State pLuaState, double i, double j) { double result; lua_getglobal(pLuaState, "Multiply"); lua_pushnumber(pLuaState, i); lua_pushnumber(pLuaState, j); lua_call(pLuaState, 2, 1); result = lua_tonumber(pLuaState, 1); lua_pop(pLuaState, 1); return result; } int main (void) { lua_State pLuaState; int attempt; int number; pLuaState = lua_open(); lua_register(pLuaState, "HAPI_Print", HAPI_Print); printf("Running script...\n"); attempt = luaL_dofile(pLuaState, "bidirectional.lua"); if (attempt != 0) { printf("error: luaL_dofile returned %d\n", attempt); return -1; } printf("Calling Multiply(2, 3): %f\n", CAPI_Multiply(pLuaState, 2, 3)); printf("Calling Multiply(5, 2): %f\n", CAPI_Multiply(pLuaState, 5, 2)); printf("Calling Multiply(1.141, 3.141): %f\n", CAPI_Multiply(pLuaState, 1.141, 3.141)); printf("Calling Test()...\n"); CAPI_Test(pLuaState); printf("Setting globals, then calling Test()...\n"); lua_pushstring(pLuaState, "Joe"); lua_setglobal(pLuaState, "FirstName"); lua_pushstring(pLuaState, "Davies"); lua_setglobal(pLuaState, "SecondName"); lua_pushstring(pLuaState, "John"); lua_setglobal(pLuaState, "ThirdName"); lua_pushstring(pLuaState, "Smith"); lua_setglobal(pLuaState, "LastName"); CAPI_Test(pLuaState); printf("Getting ImportantNumber...\n"); lua_getglobal(pLuaState, "ImportantNumber"); number = (int) lua_tonumber(pLuaState, lua_gettop(pLuaState)); lua_pop(pLuaState, 1); printf("= %d\n", number); printf("End.\n"); lua_close(pLuaState); return 0; } --v

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Bi-directional C and Lua

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