Implement As/FromLua for Option<T>

src/lib.rs

@@ -173,4 +173,23 @@ impl<'a> PushToLuaStack<'a> for bool {
         let v = self.as_lua(state)?;
         v.push_to_lua_stack(state)
     }
+}
+
+impl<'a, T: AsLua<'a>> AsLua<'a> for Option<T> {
+    fn as_lua(self, lua: &'a State) -> crate::Result<Value<'a>> {
+        match self {
+            Some(v) => v.as_lua(lua),
+            None => Ok(Value::Nil)
+        }
+    }
+}
+
+impl<'a, T: FromLua<'a>> FromLua<'a> for Option<T> {
+    fn from_lua(lua: &'a State, val: Value<'a>) -> crate::Result<Self> {
+        if val.is_nil() {
+            Ok(None)
+        } else {
+            Ok(Some(T::from_lua(lua, val)?))
+        }
+    }
 }

src/value.rs

@@ -330,7 +330,6 @@ impl<'a> From<Vec<Value<'a>>> for ValueVec<'a> {
     }
 }
 
-
 impl<'a> FromLuaStack<'a> for ValueVec<'a> {
     unsafe fn from_lua_stack(state: &'a State) -> crate::Result<Self> {
         let s = state.state_ptr();
@@ -390,6 +389,12 @@ impl<'a> ValueVec<'a> {
         T::from_lua_value_vec(lua, self)
             .map(|t| Some(t))
     }
+
+    pub fn push_val<T: AsLua<'a>>(&mut self, lua: &'a State, val: T) -> crate::Result<()> {
+        let val = val.as_lua(lua)?;
+        self.push_back(val);
+        Ok(())
+    }
 }
 
 impl<'a> From<Value<'a>> for ValueVec<'a> {