clear sstreams before seekg'ing them in Parser::parse_any_operator

libwccl/parser/Parser.cpp

@@ -139,6 +139,7 @@ boost::shared_ptr<ANTLRParserResultBase> Parser::parseAnyOperator(
 	std::stringstream errors;
 	boost::shared_ptr<ANTLRParserResultBase> result;
 	if (!result) {
+		ss.clear();
 		ss.seekg(0, std::ios::beg);
 		ANTLRLexer lexer(ss);
 		ANTLRParser parser(lexer);
@@ -150,6 +151,7 @@ boost::shared_ptr<ANTLRParserResultBase> Parser::parseAnyOperator(
 		}
 	}
 	if (!result) {
+		ss.clear();
 		ss.seekg(0, std::ios::beg);
 		ANTLRLexer lexer(ss);
 		ANTLRParser parser(lexer);
@@ -161,6 +163,7 @@ boost::shared_ptr<ANTLRParserResultBase> Parser::parseAnyOperator(
 		}
 	}
 	if (!result) {
+		ss.clear();
 		ss.seekg(0, std::ios::beg);
 		ANTLRLexer lexer(ss);
 		ANTLRParser parser(lexer);