added stdlib.lua + lua errors handling update

res/scripts/stdlib.lua

@@ -0,0 +1,51 @@
+-- kit of standard functions
+
+-- Check if given table is an array
+function is_array(x)
+    if #t > 0 then
+        return true
+    end
+    for k, v in pairs(x) do
+        return false
+    end
+    return true
+end
+
+local __cached_scripts = {}
+local __cached_results = {}
+
+-- Get entry-point and filename from `entry-point:filename` path 
+function parse_path(path)
+    local index = string.find(path, ':')
+    if index == nil then
+        error("invalid path syntax (':' missing)")
+    end
+    return string.sub(path, 1, index-1), string.sub(path, index+1, -1)
+end
+
+-- Load script with caching
+--
+-- path - script path `contentpack:filename`. 
+--     Example `base:scripts/tests.lua`
+--
+-- nocache - ignore cached script, load anyway
+function load_script(path, nocache)
+    local packname, filename = parse_path(path)
+    local packpath = pack.get_folder(packname)
+    local fullpath = packpath..filename
+
+    -- __cached_scripts used in condition because cached result may be nil
+    if not nocache and __cached_scripts[fullpath] ~= nil then
+        return __cached_results[fullpath]
+    end
+    local script = loadfile(fullpath)
+    if script == nil then
+        error("script '"..filename.."' not found in '"..packname.."'")
+    end
+    local result = script()
+    if not nocache then
+        __cached_scripts[fullpath] = script
+        __cached_results[fullpath] = result
+    end
+    return result
+end

src/logic/scripting/scripting.cpp

@@ -26,6 +26,10 @@ Level* scripting::level = nullptr;
 const Content* scripting::content = nullptr;
 BlocksController* scripting::blocks = nullptr;
 
+static void handleError(lua_State* L) {
+    std::cerr << "lua error: " << lua_tostring(L,-1) << std::endl;
+}
+
 inline int lua_pushivec3(lua_State* L, int x, int y, int z) {
     lua_pushinteger(L, x);
     lua_pushinteger(L, y);
@@ -51,13 +55,24 @@ bool rename_global(lua_State* L, const char* src, const char* dst) {
 
 int call_func(lua_State* L, int argc, const std::string& name) {
     if (lua_pcall(L, argc, LUA_MULTRET, 0)) {
-        std::cerr << "Lua error in " << name << ": ";
-        std::cerr << lua_tostring(L,-1) << std::endl;
+        handleError(L);
         return 0;
     }
     return 1;
 }
 
+void load_script(fs::path name) {
+    auto paths = scripting::engine->getPaths();
+    fs::path file = paths->getResources()/fs::path("scripts")/name;
+
+    std::string src = files::read_string(file);
+    if (luaL_loadbuffer(L, src.c_str(), src.length(), file.u8string().c_str())) {
+        handleError(L);
+        return;
+    }
+    call_func(L, 0, file.u8string());
+}
+
 void scripting::initialize(Engine* engine) {
     scripting::engine = engine;
 
@@ -81,17 +96,15 @@ void scripting::initialize(Engine* engine) {
 #   endif // LUAJIT_VERSION
 
     apilua::create_funcs(L);
+
+    load_script(fs::path("stdlib.lua"));
 }
 
 void scripting::on_world_load(Level* level, BlocksController* blocks) {
     scripting::level = level;
     scripting::content = level->content;
     scripting::blocks = blocks;
-    auto paths = scripting::engine->getPaths();
-    fs::path file = paths->getResources()/fs::path("scripts/world.lua");
-    std::string src = files::read_string(file);
-    luaL_loadbuffer(L, src.c_str(), src.length(), file.string().c_str());
-    call_func(L, 0, "<script>");
+    load_script("world.lua");
 }
 
 void scripting::on_world_quit() {
@@ -165,7 +178,7 @@ void scripting::load_block_script(std::string prefix, fs::path file, block_funcs
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
     if (luaL_loadbuffer(L, src.c_str(), src.size(), file.string().c_str())) {
-        std::cerr << "Lua error:" << lua_tostring(L,-1) << std::endl;
+        handleError(L);
         return;
     }
     call_func(L, 0, "<script>");
@@ -181,7 +194,7 @@ void scripting::load_item_script(std::string prefix, fs::path file, item_funcs_s
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
     if (luaL_loadbuffer(L, src.c_str(), src.size(), file.string().c_str())) {
-        std::cerr << "Lua error:" << lua_tostring(L,-1) << std::endl;
+        handleError(L);
         return;
     }
     call_func(L, 0, "<script>");