Yes. May need to back track due to context sensitivity. A quote from the source comments: Some C++ constructs require arbitrary look ahead to disambiguate.

Yes. May need to back track due to context sensitivity. A quote from the source comments: Some C++ constructs require arbitrary look ahead to disambiguate. For example, it is impossible, in the general case, to tell whether a statement is an expression or declaration without scanning the entire statement. I am sure there must be some devilish source code examples that require an exponential search for the correct parse. Also, has anyone constructed a modern C++ parser in bison which can backtrack?