Boost Spirit Signals Successful Parsing Despite Token Being Incomplete

Question

I have a very simple path construct that I am trying to parse with boost spirit.lex.

We have the following grammar:

token := [a-z]+
path := (token :          


        

Answer 1

The problem lies in the meaning of first and last after your call to tokenize_and_parse. first==last checks if your string has been completely tokenized, you can't infer anything about grammar. If you isolate the parsing like this, you obtain the expected result:

  PathTokens tokens;
  PathGrammar grammar(tokens);

  BaseIteratorType first = str.begin();
  BaseIteratorType last = str.end();

  LexerType::iterator_type lexfirst = tokens.begin(first,last);
  LexerType::iterator_type lexlast = tokens.end();


  bool r = parse(lexfirst, lexlast, grammar);

  std::cerr << r << " " << (lexfirst==lexlast) << "\n";