lua: Make LuaState Lua 5.2 compatible

taminob · Mar 20, 2024 · b9d2d78 · b9d2d78
1 parent 6b432be
commit b9d2d78
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Showing 3 changed files with 18 additions and 4 deletions.
diff --git a/include/lua/lua_script.h b/include/lua/lua_script.h
@@ -34,7 +34,7 @@ class LuaScript {
             if (auto function = state_.top<ReturnValue(Args...)>()) {
                 return (*function)(std::forward<Args>(args)...);
             }
-            return { CallError::Code::unknown };
+            return CallError { CallError::Code::unknown, "Symbol does not match given type" };
         }
         return { CallError::Code::symbolNotFound };
     }

diff --git a/include/lua/lua_state.h b/include/lua/lua_state.h
@@ -119,6 +119,11 @@ class LuaState {
     auto topFunction();
     const void* topPointer();
 
+    /**
+     * Check if top-most stack value is of type nil.
+     */
+    bool isNil();
+
     /**
      * Pop top-most value if it is a function.
      *

diff --git a/src/lua_state.cpp b/src/lua_state.cpp
@@ -14,7 +14,7 @@ extern "C" {
 namespace {
 constexpr auto MINIMUM_LUA_VERSION = 502;
 } // namespace
-static_assert(LUA_VERSION_NUM > MINIMUM_LUA_VERSION);
+static_assert(LUA_VERSION_NUM >= MINIMUM_LUA_VERSION);
 
 namespace ppplugin {
 LuaState::LuaState()
@@ -127,6 +127,11 @@ bool LuaState::isFunction()
     return lua_type(state(), -1) == LUA_TFUNCTION;
 }
 
+bool LuaState::isNil()
+{
+    return lua_type(state(), -1) == LUA_TNIL;
+}
+
 void LuaState::registerPanicHandler(LuaCFunction handler)
 {
     lua_atpanic(state(), handler);
@@ -145,7 +150,11 @@ void LuaState::markGlobal(const std::string& variable_name)
 
 bool LuaState::pushGlobal(const std::string& variable_name)
 {
-    auto type = lua_getglobal(state(), variable_name.c_str());
-    return type != LUA_TNONE;
+    lua_getglobal(state(), variable_name.c_str());
+    if (isNil()) {
+        discardTop();
+        return false;
+    }
+    return true;
 }
 } // namespace ppplugin