1 files changed, 11 insertions, 0 deletions

diff --git a/c-embed-lua/main.c b/c-embed-lua/main.c
index 7ab678a..662ea70 100644
--- a/c-embed-lua/main.c
+++ b/c-embed-lua/main.c
@@ -4,10 +4,21 @@
 
 #include "hi.h"
 
+static int l_sum(lua_State *L) {
+        double a = luaL_checknumber(L, 1);
+        double b = luaL_checknumber(L, 2);
+        lua_pushnumber(L, a + b);
+        return 1;
+}
+
 int main(void) {
         lua_State *L = luaL_newstate();
         luaL_openlibs(L);
 
+        // You do not need to prefix name of the function with `c_`. I did it to
+        // make it clear in the lua script code that this is a custom function.
+        lua_register(L, "c_sum", l_sum);
+
         // Not wise since this is not a null-terminated string.
         /* luaL_dostring(L, (const char*)hi); */