Function ll_require

Source/Misc/lua/src/lua.c:13219–13262

static int ll_require (lua_State *L) {
const char *name = luaL_checkstring(L, 1);
int i;
lua_settop(L, 1);  /* _LOADED table will be at index 2 */
lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
lua_getfield(L, 2, name);
if (lua_toboolean(L, -1)) {  /* is it there? */
if (lua_touserdata(L, -1) == sentinel)  /* check loops */
luaL_error(L, "loop or previous error loading module " LUA_QS, name);
return 1;  /* package is already loaded */
}
/* else must load it; iterate over available loaders */
lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
if (!lua_istable(L, -1))
luaL_error(L, LUA_QL("package.loaders") " must be a table");
lua_pushliteral(L, "");  /* error message accumulator */
for (i=1; ; i++) {
lua_rawgeti(L, -2, i);  /* get a loader */
if (lua_isnil(L, -1))
luaL_error(L, "module " LUA_QS " not found:%s",
name, lua_tostring(L, -2));
lua_pushstring(L, name);
lua_call(L, 1, 1);  /* call it */
if (lua_isfunction(L, -1))  /* did it find module? */
break;  /* module loaded successfully */
else if (lua_isstring(L, -1))  /* loader returned error message? */
lua_concat(L, 2);  /* accumulate it */
else
lua_pop(L, 1);
}
lua_pushlightuserdata(L, sentinel);
lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
lua_pushstring(L, name);  /* pass name as argument to module */
lua_call(L, 1, 1);  /* run loaded module */
if (!lua_isnil(L, -1))  /* non-nil return? */
lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
lua_getfield(L, 2, name);
if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
lua_pushboolean(L, 1);  /* use true as result */
lua_pushvalue(L, -1);  /* extra copy to be returned */
lua_setfield(L, 2, name);  /* _LOADED[name] = true */
}
return 1;
}

/* }====================================================== */