Add UserDataProxy

src/main.rs

@@ -37,7 +37,8 @@ fn main() -> Result<()> {
     let f = lua.create_function(a)?;
     globals.set("native_test", f)?;
     
-    let ud = lua.create_userdata("Vec2", Vec2 { x: 0.0, y: 0.0})?;
+    //let ud = lua.create_userdata("Vec2", Vec2 { x: 0.0, y: 0.0})?;
+    let ud = lua.create_userdata("Vec2", UserdataProxy::<Vec2>::new())?;
     globals.set("Vec2", ud)?;
 
     let tbl = lua.create_table()?;
@@ -90,7 +91,7 @@ fn main() -> Result<()> {
         print("Vec2: " .. dump_table(Vec2))
         print("Meta Vec2: " .. dump_table(getmetatable(Vec2)))
         
-        print("Vec2 is (" .. Vec2.x .. ", " .. Vec2.y .. ")")
+        --print("Vec2 is (" .. Vec2.x .. ", " .. Vec2.y .. ")")
 
         local v1 = Vec2.new(50, 50)
         print("v1 is (" .. v1.x .. ", " .. v1.y .. ")")
@@ -172,6 +173,11 @@ pub enum Error {
         /// the error that describes what was wrong for this argument
         error: Arc<Error>
     },
+    #[error("Incorrect number of arguments, expected {arg_expected}, got {arg_count}")]
+    IncorrectArgCount {
+        arg_expected: i32,
+        arg_count: i32,
+    },
     #[error("There is already a registry entry with the key {0}")]
     RegistryConflict(String)
 }
@@ -189,7 +195,7 @@ impl Error {
     /// 
     /// This method never returns
     pub unsafe fn throw_lua(self, lua: *mut lua::lua_State) -> ! {
-        let msg = format!("{}", self);
+        let msg = format!("{}\0", self);
         let msg_c = msg.as_ptr() as *const i8;
         lua::luaL_error(lua, msg_c);
         unreachable!();
@@ -268,18 +274,6 @@ impl<'a> PushToLuaStack<'a> for String {
     }
 }
 
-/* impl<'a> FromLuaStack<'a> for String {
-    unsafe fn from_lua_stack(state: &'a State) -> Result<Self> {
-        let s = state.state_ptr();
-
-        let cstr = lua::lua_tostring(s, -1);
-        lua::lua_pop(s, 1);
-
-        let cstr = CStr::from_ptr(cstr);
-        Ok(cstr.to_str().unwrap().to_string())
-    }
-} */
-
 impl<'a> FromLua<'a> for String {
     fn from_lua(_lua: &State, val: Value) -> crate::Result<Self> {
         val.as_string().cloned()
@@ -315,6 +309,18 @@ impl Userdata for Vec2 {
             .function("new", |lua, (x, y)| {
                 lua.create_userdata("Vec2", Vec2 { x, y, })
             })
+
+            // method test
+            .method("add", |lua, lhs: &Vec2, (rhs,): (&Vec2,)| {
+                let lx = lhs.x;
+                let ly = lhs.y;
+
+                let rx = rhs.x;
+                let ry = rhs.y;
+                
+                lua.create_userdata("Vec2", Vec2 { x: lx + rx, y: ly + ry, })
+            })
+
             .meta_method(MetaMethod::Add, |lua, lhs: &Vec2, (rhs,): (&Vec2,)| {
                 let lx = lhs.x;
                 let ly = lhs.y;
@@ -349,14 +355,11 @@ impl<T: Userdata> Userdata for UserdataProxy<T> {
         let mut other = UserdataBuilder::<T>::new();
         T::build(&mut other)?;
 
-        builder.name(&other.name.unwrap());
+        let name = format!("{}Proxy", other.name.unwrap());
+        builder.name = Some(name);
 
-        /* for (lbl, getters) in other.field_getters.into_iter() {
-            let wrap = |state: &State, data: &Self| {
-                Ok(())
-            };
-            builder.field_getter(&lbl, wrap);
-        } */
+        // only the functions need to be added since they're the only thing usable from a proxy
+        builder.functions = other.functions;
 
         Ok(())
     }

src/state.rs

@@ -323,6 +323,7 @@ impl State {
             let lua_func = self.create_function(move |lua: &State, vals: ValueVec| {
                 func(lua, vals)
             })?;
+            
             // Safety: This will be alive for as long as the lua state is alive
             let lua_func: Function<'_> = unsafe { mem::transmute(lua_func) };
             fns_table.insert(func_name, lua_func);
@@ -332,7 +333,7 @@ impl State {
 
         // dont create an index function if there are no getters,
         // or if an index metamethod was defined
-        if !getters.is_empty() || !builder.meta_methods.contains_key("__index") {
+        if (!getters.is_empty() || !fns_table.is_empty()) || !builder.meta_methods.contains_key("__index") {
             let index_fn = self.create_function(move |lua: &State, (ud, key): (AnyUserdata, String)| {
                 if let Some(getter) = getters.get(&key) {
                     let r = getter(lua, ValueVec::from(Value::Userdata(ud)))?;
@@ -360,7 +361,7 @@ impl State {
                     
                     Ok(Value::None)
                 } else {
-                    Ok(Value::Nil)
+                    Err(Error::Runtime(format!("attempt to assign a nil field, {}", key)))
                 }
             })?;
 

src/value.rs

@@ -238,7 +238,10 @@ macro_rules! impl_from_lua_vec_tuple {
       
             fn from_lua_value_vec(state: &'a State, mut values: ValueVec<'a>) -> crate::Result<Self> {
                 if values.len() != $count {
-                    panic!("Not same length"); // TODO
+                    return Err(crate::Error::IncorrectArgCount {
+                        arg_expected: $count,
+                        arg_count: values.len() as i32,
+                    });
                 }
 
                 let f = $first::from_lua(state, values.pop_front().unwrap())?;
@@ -256,7 +259,10 @@ macro_rules! impl_from_lua_vec_tuple {
         impl<'a, $only: FromLua<'a>> FromLuaVec<'a> for ($only,) {
             fn from_lua_value_vec(state: &'a State, mut values: ValueVec<'a>) -> crate::Result<Self> {
                 if values.len() != 1 {
-                    panic!("Not same length"); // TODO
+                    return Err(crate::Error::IncorrectArgCount {
+                        arg_expected: 1,
+                        arg_count: $count,
+                    });
                 }
 
                 Ok( ( $only::from_lua(state, values.pop_front().unwrap())?, ) )