Add 'ParseReturnValuesOnly' to the lua prototype parser.

Source/Integration/LuaCall.cpp

@@ -91,10 +91,7 @@ void FlxParsedProto::Syntax() {
 	ErrorMessage = Message;
 }
 
-void FlxParsedProto::Parse(const FString &str) {
+bool FlxParsedProto::Tokenize(const FString &str) {
-	Empty();
-
-	// Step one: tokenize.
 	int offset = 0;
 	while (offset < str.Len()) {
 		TCHAR c = str[offset];
@@ -113,12 +110,33 @@ void FlxParsedProto::Parse(const FString &str) {
 		} else {
 			Empty();
 			ErrorMessage = FString::Printf(TEXT("%s  ?  %s"), *str.Mid(0, offset), *str.Mid(offset));
-			return;
+			return false;
 		}
 	}
 	NextToken = 0;
+	return true;
+}
 
-	// Step two: Parse.
+void FlxParsedProto::ParseReturnValues() {
+	while (true) {
+		if (IsLiteral(TEXT("..."))) {
+			ExtraReturnValues = true;
+			NextToken++;
+			break;
+		} else if (IsIdent()) {
+			FString Type = Tokens[NextToken++];
+			if (!IsIdent()) return Syntax();
+			FString Name = Tokens[NextToken++];
+			ReturnValues.Add(Pin(Type, Name));
+			if (!IsLiteral(TEXT(","))) break;
+			NextToken++;
+		} else {
+			return Syntax();
+		}
+	}
+}
+
+void FlxParsedProto::Parse() {
 	if (!IsLiteral(TEXT("*")) && !IsIdent()) return Syntax();
 	ClassName = Tokens[NextToken++];
 	if (!IsLiteral(TEXT("."))) return Syntax();
@@ -142,24 +160,24 @@ void FlxParsedProto::Parse(const FString &str) {
 	NextToken++;
 	if (IsLiteral(TEXT(":"))) {
 		NextToken++;
-		while (true) {
+		ParseReturnValues();
-			if (IsLiteral(TEXT("..."))) {
-				ExtraReturnValues = true;
-				NextToken++;
-				break;
-			} else if (IsIdent()) {
-				FString Type = Tokens[NextToken++];
-				if (!IsIdent()) return Syntax();
-				FString Name = Tokens[NextToken++];
-				ReturnValues.Add(Pin(Type, Name));
-				if (!IsLiteral(TEXT(","))) break;
-				NextToken++;
-			} else {
-				return Syntax();
 	}
 }
+
+FlxParsedProto FlxParsedProto::ParsePrototype(const FString &str) {
+	FlxParsedProto Result;
+	if (!Result.Tokenize(str)) return Result;
+	Result.Parse();
+	if (Result.NextToken != Result.Tokens.Num()) Result.Syntax();
+	return Result;
 }
-	if (NextToken != Tokens.Num()) return Syntax();
+
+FlxParsedProto FlxParsedProto::ParseReturnValuesOnly(const FString &str) {
+	FlxParsedProto Result;
+	if (!Result.Tokenize(str)) return Result;
+	Result.ParseReturnValues();
+	if (Result.NextToken != Result.Tokens.Num()) Result.Syntax();
+	return Result;
 }
 
 /////////////////////////////////////////////////////////////////

Source/Integration/LuaCall.h

@@ -86,14 +86,29 @@ private:
 	//
 	void Empty();
 
-	// Parse a function prototype.
+	// Parse comma-separated "type name" pairs into ReturnValues.
 	//
-	void Parse(const FString &proto);
+	void ParseReturnValues();
+
+	// Parse a full function prototype (assumes already tokenized).
+	//
+	void Parse();
+
+	// Tokenize the input string.
+	//
+	bool Tokenize(const FString &str);
 
 public:
-	// Construct with a prototype.
+	// Parse a full function prototype.
 	//
-	FlxParsedProto(const FString &str) { Parse(str); }
+	static FlxParsedProto ParsePrototype(const FString &str);
+
+	// Parse just a comma-separated list of "type name" pairs.
+	//
+	static FlxParsedProto ParseReturnValuesOnly(const FString &str);
+
+private:
+	FlxParsedProto() { Empty(); }
 };
 
 ////////////////////////////////////////////////////////////

Source/Integration/LuaCallNode.cpp

@@ -72,7 +72,7 @@ void UK2Node_LuaInvoke::AllocateDefaultPins()
 	// Note that we use the saved value of the function
 	// prototype, because the function prototype pin
 	// has been deleted at this point.
-	FlxParsedProto ParsedProto(LuaFunctionPrototype);
+	FlxParsedProto ParsedProto = FlxParsedProto::ParsePrototype(LuaFunctionPrototype);
 	if (!ParsedProto.ErrorMessage.IsEmpty())
 	{
 		SetErrorMsg(FString::Printf(TEXT("Syntax error in lua function prototype: %s"), *ParsedProto.ErrorMessage));
@@ -164,7 +164,7 @@ void UK2Node_LuaInvoke::ExpandNode(class FKismetCompilerContext& CompilerContext
 {
 	Super::ExpandNode(CompilerContext, SourceGraph);
 	// The BeginNode function packs the class name and function name into the call buffer.
-	FlxParsedProto ParsedProto(LuaFunctionPrototype);
+	FlxParsedProto ParsedProto = FlxParsedProto::ParsePrototype(LuaFunctionPrototype);
 	const UEdGraphSchema_K2* CCSchema = CompilerContext.GetSchema();
 	UK2Node_CallFunction* BeginNode = MakeCallFunctionNode(CompilerContext, SourceGraph, LuaCallLibraryFunction(LuaCallBegin));
 	CCSchema->TrySetDefaultValue(*BeginNode->FindPinChecked(TEXT("ClassName")), ParsedProto.ClassName);

Source/Integration/ReadLuaValues.cpp

@@ -72,7 +72,7 @@ void UK2Node_ReadLuaValues::AllocateDefaultPins()
 	// Note that we use the saved value of the function
 	// prototype, because the function prototype pin
 	// has been deleted at this point.
-	FlxParsedProto ParsedProto(LuaFunctionPrototype);
+	FlxParsedProto ParsedProto = FlxParsedProto::ParsePrototype(LuaFunctionPrototype);
 	if (!ParsedProto.ErrorMessage.IsEmpty())
 	{
 		SetErrorMsg(FString::Printf(TEXT("Syntax error in lua function prototype: %s"), *ParsedProto.ErrorMessage));
@@ -164,7 +164,7 @@ void UK2Node_ReadLuaValues::ExpandNode(class FKismetCompilerContext& CompilerCon
 {
 	Super::ExpandNode(CompilerContext, SourceGraph);
 	// The BeginNode function packs the class name and function name into the call buffer.
-	FlxParsedProto ParsedProto(LuaFunctionPrototype);
+	FlxParsedProto ParsedProto = FlxParsedProto::ParsePrototype(LuaFunctionPrototype);
 	const UEdGraphSchema_K2* CCSchema = CompilerContext.GetSchema();
 	UK2Node_CallFunction* BeginNode = MakeCallFunctionNode(CompilerContext, SourceGraph, LuaCallLibraryFunction(LuaCallBegin));
 	CCSchema->TrySetDefaultValue(*BeginNode->FindPinChecked(TEXT("ClassName")), ParsedProto.ClassName);