shiny new load_result type, and thusly we're ready for 2.5.

docs/source/api/state.rst

@@ -60,11 +60,12 @@ These functions run the desired blob of either code that is in a string, or code
 
 .. code-block:: cpp
 	:caption: function: load / load_file
+	:name: state-load-code
 
-	sol::stack_proxy load(const std::string& code);
-	sol::stack_proxy load_file(const std::string& filename);
+	sol::load_result load(const std::string& code);
+	sol::load_result load_file(const std::string& filename);
 
-These functions *load* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It will not run: it returns a proxy that can be called, turned into a `sol::function`,. or similar, will run the loaded code.
+These functions *load* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It will not run: it returns a ``load_result`` proxy that can be called, turned into a `sol::function`,. or similar, will run the loaded code.
 
 .. code-block:: cpp
 	:caption: function: global table / registry table

docs/source/api/types.rst

@@ -40,17 +40,31 @@ This strongly-typed enumeration contains the errors potentially generated by a c
 	:name: thread-status
 	
 	enum class thread_status : int {
-	    normal        = LUA_OK,
+	    ok  = LUA_OK,
 	    yielded = LUA_YIELD,
-	    error_runtime = LUA_ERRRUN,
-	    error_memory  = LUA_ERRMEM,
-	    error_gc      = LUA_ERRGCMM,
-	    error_handler = LUA_ERRERR,
+	    runtime = LUA_ERRRUN,
+	    memory  = LUA_ERRMEM,
+	    gc      = LUA_ERRGCMM,
+	    handler = LUA_ERRERR,
 	    dead,
 	};
 
 This enumeration contains the status of a thread. The ``thread_status::dead`` state is generated when the thread has nothing on its stack and it is not running anything.
 
+.. code-block:: cpp
+	:caption: status of a Lua load operation
+	:name: load-status
+	
+	enum class load_status : int {
+	    ok      = LUA_OK,
+	    runtime = LUA_ERRSYNTAX,
+	    memory  = LUA_ERRMEM,
+	    gc      = LUA_ERRGCMM,
+	    file    = LUA_ERRFILE,
+	};
+
+This enumeration contains the status of a load operation from :ref:`state::load(_file)<state-load-code>`. The ``thread_status::dead`` state is generated when the thread has nothing on its stack and it is not running anything.
+
 .. code-block:: cpp
 	:caption: type enumeration
 	:name: type-enum

docs/source/tutorial/all-the-things.rst

@@ -34,6 +34,8 @@ For your system/game that already has lua, but you'd like something nice:
 running lua code
 ----------------
 
+.. code-block:: cpp
+
 	sol::state lua;
 	// load and execute from string
 	lua.script("a = 'test'");
@@ -57,17 +59,26 @@ You can set/get everything.
 	
 	sol::lua_state lua;
 
-	lua.set("number", 24); // integer types
-	lua["number2"] = 24.5; // floating point numbers
-	lua["important_string"] = "woof woof"; // becomes string
-	lua["myuserdata"] = some_class(); // non-recognized types is stored as userdata
-	lua["a_function"] = [](){ return 100; }; // is callable, therefore gets stored as a function
+	// integer types
+	lua.set("number", 24);
+	// floating point numbers
+	lua["number2"] = 24.5;
+	// string types
+	lua["important_string"] = "woof woof";
+	// non-recognized types is stored as userdata
+	lua["myuserdata"] = some_class();
+	// is callable, therefore gets stored as a function
+	lua["a_function"] = [](){ return 100; }; 
 
-	int number = lua["number"]; // implicit conversion
-	auto number2 = lua.get<double>("number2"); // explicit get
-	std::string important_string = lua["important_string"]; // strings too
+	// implicit conversion
+	int number = lua["number"];
+	// explicit get
+	auto number2 = lua.get<double>("number2");
+	// strings too
+	std::string important_string = lua["important_string"];
 	
-	some_class& myuserdata = lua["myuserdata"]; // returns a plain reference
+	// returns a plain reference
+	some_class& myuserdata = lua["myuserdata"];
 	// myuserdata.some_variable = 20  WILL (!!) modify 
 	// data inside of lua VM as well, if you get a pointer or a reference
 	

sol/load_result.hpp

@@ -0,0 +1,139 @@
+// The MIT License (MIT) 
+
+// Copyright (c) 2013-2016 Rapptz, ThePhD and contributors
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#ifndef SOL_LOAD_RESULT_HPP
+#define SOL_LOAD_RESULT_HPP
+
+#include "stack.hpp"
+#include "function.hpp"
+#include "proxy_base.hpp"
+#include <cstdint>
+
+namespace sol {
+	struct load_result : public proxy_base<load_result> {
+	private:
+		lua_State* L;
+		int index;
+		int returncount;
+		int popcount;
+		load_status err;
+
+		template <typename T>
+		decltype(auto) tagged_get(types<sol::optional<T>>) const {
+			if (!valid()) {
+				return sol::optional<T>(nullopt);
+			}
+			return stack::get<sol::optional<T>>(L, index);
+		}
+
+		template <typename T>
+		decltype(auto) tagged_get(types<T>) const {
+#ifdef SOL_CHECK_ARGUMENTS
+			if (!valid()) {
+				type_panic(L, index, type_of(L, index), type::none);
+			}
+#endif // Check Argument Safety
+			return stack::get<T>(L, index);
+		}
+
+		sol::optional<sol::error> tagged_get(types<sol::optional<sol::error>>) const {
+			if (valid()) {
+				return nullopt;
+			}
+			return sol::error(detail::direct_error, stack::get<std::string>(L, index));
+		}
+
+		sol::error tagged_get(types<sol::error>) const {
+#ifdef SOL_CHECK_ARGUMENTS
+			if (valid()) {
+				type_panic(L, index, type_of(L, index), type::none);
+			}
+#endif // Check Argument Safety
+			return sol::error(detail::direct_error, stack::get<std::string>(L, index));
+		}
+
+	public:
+		load_result() = default;
+		load_result(lua_State* L, int index = -1, int returncount = 0, int popcount = 0, load_status err = load_status::ok) : L(L), index(index), returncount(returncount), popcount(popcount), err(err) {
+
+		}
+		load_result(const load_result&) = default;
+		load_result& operator=(const load_result&) = default;
+		load_result(load_result&& o) : L(o.L), index(o.index), returncount(o.returncount), popcount(o.popcount), err(o.err) {
+			// Must be manual, otherwise destructor will screw us
+			// return count being 0 is enough to keep things clean
+			// but will be thorough
+			o.L = nullptr;
+			o.index = 0;
+			o.returncount = 0;
+			o.popcount = 0;
+			o.err = load_status::syntax;
+		}
+		load_result& operator=(load_result&& o) {
+			L = o.L;
+			index = o.index;
+			returncount = o.returncount;
+			popcount = o.popcount;
+			err = o.err;
+			// Must be manual, otherwise destructor will screw us
+			// return count being 0 is enough to keep things clean
+			// but will be thorough
+			o.L = nullptr;
+			o.index = 0;
+			o.returncount = 0;
+			o.popcount = 0;
+			o.err = load_status::syntax;
+			return *this;
+		}
+
+		load_status error() const {
+			return err;
+		}
+
+		bool valid() const {
+			return error() == load_status::ok;
+		}
+
+		template<typename T>
+		T get() const {
+			return tagged_get(types<meta::Unqualified<T>>());
+		}
+
+		template<typename... Ret, typename... Args>
+		decltype(auto) call(Args&&... args) {
+			return get<function>().template call<Ret...>(std::forward<Args>(args)...);
+		}
+
+		template<typename... Args>
+		decltype(auto) operator()(Args&&... args) {
+			return call<>(std::forward<Args>(args)...);
+		}
+
+		lua_State* lua_state() const { return L; };
+		int stack_index() const { return index; };
+
+		~load_result() {
+			stack::remove(L, index, popcount);
+		}
+	};
+} // sol
+
+#endif // SOL_LOAD_RESULT_HPP

sol/protected_function_result.hpp

@@ -73,7 +73,7 @@ private:
 
 public:
     protected_function_result() = default;
-    protected_function_result(lua_State* L, int index = -1, int returncount = 0, int popcount = 0, call_status error = call_status::ok): L(L), index(index), returncount(returncount), popcount(popcount), err(error) {
+    protected_function_result(lua_State* L, int index = -1, int returncount = 0, int popcount = 0, call_status err = call_status::ok): L(L), index(index), returncount(returncount), popcount(popcount), err(err) {
         
     }
     protected_function_result(const protected_function_result&) = default;
@@ -127,4 +127,4 @@ public:
 };
 } // sol
 
-#endif // SOL_FUNCTION_RESULT_HPP
+#endif // SOL_PROTECTED_FUNCTION_RESULT_HPP

sol/stack_reference.hpp

@@ -46,6 +46,10 @@ public:
         return 1;
     }
 
+    void pop(int n = 1) const noexcept {
+        lua_pop(lua_state( ), n);
+    }
+
     int stack_index () const noexcept {
         return index;
     }
@@ -58,6 +62,11 @@ public:
     lua_State* lua_state() const noexcept {
         return L;
     }
+
+    bool valid () const noexcept {
+        type t = get_type();
+        return t != type::nil && t != type::none;
+    }
 };
 } // sol
 

sol/state_view.hpp

@@ -24,6 +24,7 @@
 
 #include "error.hpp"
 #include "table.hpp"
+#include "load_result.hpp"
 #include <memory>
 
 namespace sol {
@@ -157,14 +158,14 @@ public:
         }
     }
 
-    stack_proxy load(const std::string& code) {
-        luaL_loadstring(L, code.c_str());
-        return stack_proxy(L, -1);
+    load_result load(const std::string& code) {
+        load_status x = static_cast<load_status>(luaL_loadstring(L, code.c_str()));
+        return load_result(L, -1, 1, 1, x);
     }
 
-    stack_proxy load_file(const std::string& filename) {
-        luaL_loadfile(L, filename.c_str());
-        return stack_proxy(L, -1);
+    load_result load_file(const std::string& filename) {
+        load_status x = static_cast<load_status>(luaL_loadfile(L, filename.c_str()));
+        return load_result(L, -1, 1, 1, x);
     }
 
     iterator begin () const {

sol/thread.hpp

@@ -52,7 +52,7 @@ public:
     thread_status status () const {
         lua_State* lthread = thread_state();
         thread_status lstat = static_cast<thread_status>(lua_status(lthread));
-        if (lstat != thread_status::normal && lua_gettop(lthread) == 0) {
+        if (lstat != thread_status::ok && lua_gettop(lthread) == 0) {
             // No thing on the thread's stack means its dead
             return thread_status::dead;
         }

sol/types.hpp

@@ -158,15 +158,23 @@ enum class call_status : int {
 };
 
 enum class thread_status : int {
-    normal        = LUA_OK,
+    ok      = LUA_OK,
     yielded = LUA_YIELD,
-    error_runtime = LUA_ERRRUN,
-    error_memory  = LUA_ERRMEM,
-    error_gc      = LUA_ERRGCMM,
-    error_handler = LUA_ERRERR,
+    runtime = LUA_ERRRUN,
+    memory  = LUA_ERRMEM,
+    gc      = LUA_ERRGCMM,
+    handler = LUA_ERRERR,
     dead,
 };
 
+enum class load_status : int {
+    ok        = LUA_OK,
+    syntax    = LUA_ERRSYNTAX,
+    memory    = LUA_ERRMEM,
+    gc        = LUA_ERRGCMM,
+    file      = LUA_ERRFILE,
+};
+
 enum class type : int {
     none          = LUA_TNONE,
     nil           = LUA_TNIL,