> if the code generated by flex and bison is re-entrant
This has been fixed long ago, you can definitely get reentrant parsers if you need to. Also, I don't know the SIP grammar, but fwiw, I'm able to write an extremely clean recursive descent parser in C++ (1); for simple grammars, it's often an overkill to go the flex/bison route. Also by "writing code to parse messages in C++" someone familiar with boost might be thinking about using boost::spirit. That's not necessarily a bad choice.
(1) Just looked - it's in fact too complex for that; but the point is, the right tools are dependent on the skillset of the person who answers, which may be different from your own/ your team's. Just because you find writing parser by hand daunting, doesn't mean that I do (I taught compiler design at the university, worked on a commercial C++ compiler, wrote many parsers).
Your interview question is good - but the key to it is the "why" part, not the answer of "how would you do it". And it's simply a different sort of question - your question tests the mindset + domain knowledge; The "reverse a linked list" question aims at filtering-out the developers that are not worth loosing time with. A developer that can't reverse a linked list is completely useless in a C++ project (in fact, his contribution is likely to be negative - doing more damage than adding value).
This has been fixed long ago, you can definitely get reentrant parsers if you need to. Also, I don't know the SIP grammar, but fwiw, I'm able to write an extremely clean recursive descent parser in C++ (1); for simple grammars, it's often an overkill to go the flex/bison route. Also by "writing code to parse messages in C++" someone familiar with boost might be thinking about using boost::spirit. That's not necessarily a bad choice.
(1) Just looked - it's in fact too complex for that; but the point is, the right tools are dependent on the skillset of the person who answers, which may be different from your own/ your team's. Just because you find writing parser by hand daunting, doesn't mean that I do (I taught compiler design at the university, worked on a commercial C++ compiler, wrote many parsers).
Your interview question is good - but the key to it is the "why" part, not the answer of "how would you do it". And it's simply a different sort of question - your question tests the mindset + domain knowledge; The "reverse a linked list" question aims at filtering-out the developers that are not worth loosing time with. A developer that can't reverse a linked list is completely useless in a C++ project (in fact, his contribution is likely to be negative - doing more damage than adding value).