Lua 'advanced' example

lua_advanced/Makefile

@@ -0,0 +1,15 @@
+CC = gcc
+CFLAGS = -Wall -O2
+
+TARGET = main.elf
+SRC = main.c
+
+LDFLAGS += -lm
+LDFLAGS += -llua
+
+$(TARGET): $(SRC)
+	@echo CC $@
+	@$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET)

lua_advanced/main.c

@@ -0,0 +1,63 @@
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+#include <stdio.h>
+#include <string.h>
+
+typedef struct {
+    float x, y, z;
+} Vec3;
+
+Vec3 table_to_vec3(lua_State *L, int index) {
+    Vec3 v;
+    luaL_checktype(L, index, LUA_TTABLE);
+
+    lua_getfield(L, index, "x");
+    v.x = luaL_checknumber(L, -1);
+    lua_pop(L, 1);
+
+    lua_getfield(L, index, "y");
+    v.y = luaL_checknumber(L, -1);
+    lua_pop(L, 1);
+
+    lua_getfield(L, index, "z");
+    v.z = luaL_checknumber(L, -1);
+    lua_pop(L, 1);
+
+    return v;
+}
+
+int printvec(lua_State *L) {
+    Vec3 v = table_to_vec3(L, 1);
+    // lua_pushnumber(L, a + b);
+    printf("{ X: %.1f, Y: %.1f, Z: %.1f }\n", v.x, v.y, v.z);
+    return 0; // no return values
+}
+
+int main(void) {
+    // Vec3 pos = {1.0, 2.0, 3.0};
+
+    // printf("{ X: %.1f, Y: %.1f, Z: %.1f }\n", pos.x, pos.y, pos.z);
+
+    lua_State *L = luaL_newstate();
+
+    luaL_openlibs(L); // Load Lua standard libraries
+    // luaL_requiref(L, "_G", luaopen_base, 1);
+
+    // const lua_Number ver = lua_version(NULL);
+
+    // printf("Lua version: %.2f\n", ver);
+    // printf("Lua version: %s\n", LUA_VERSION);
+
+    // Register the C function as a global Lua function
+    lua_register(L, "printvec", printvec);
+
+    // Run the Lua script
+    if (luaL_dofile(L, "script.lua") != LUA_OK) {
+        fprintf(stderr, "Error: %s\n", lua_tostring(L, -1));
+        lua_pop(L, 1); // remove error message
+    }
+
+    lua_close(L);
+    return 0;
+}

lua_advanced/script.lua

@@ -0,0 +1,13 @@
+---@meta
+
+---@class Vec3
+---@field x number
+---@field y number
+---@field z number
+
+---Prints a vector
+---@param v Vec3
+function printvec(v) end
+
+vec = { x = 1.0, y = 2.0, z = 3.0 }
+printvec(vec)