missing expectation errors for program fragments

[bob-carpenter]

Summary:

When the program ends in the middle of a Boost Spirit Qi parser expectation, the error doesn't get reported.

Reproducible Steps:

This program triggers the problem.

oneliner.stan

data {

Current Output:

From CmdStan:

Model name=oneliner_model
Input file=/Users/carp/temp2/oneliner.stan
Output file=/Users/carp/temp2/oneliner.hpp

PROGRAM ERROR, MESSAGE(S) FROM PARSER:


make: *** [/Users/carp/temp2/oneliner.hpp] Error 253

Expected Output:

Expectation error indicating a missing }.

Additional Information:

I tried to ask on StackOverflow and got scolded and downvoted.

https://stackoverflow.com/questions/45307175/expectation-failure-not-triggered-if-file-ends-with-boost-spirit-qi-parser/45307497#45307497

I've gotten this far in trying to replicate with no luck, so I'm going to punt on this for the time being.

#include <boost/spirit/home/support/iterators/line_pos_iterator.hpp>
#include <boost/spirit/include/qi.hpp>
#include <string>
#include <iostream>

namespace test {
  using namespace boost::spirit::qi;

  typedef std::string::const_iterator input_iterator;
  typedef boost::spirit::line_pos_iterator<input_iterator> lp_iterator;

  struct whitespace_grammar : public boost::spirit::qi::grammar<lp_iterator> {
    boost::spirit::qi::rule<lp_iterator> whitespace;
    whitespace_grammar() : whitespace_grammar::base_type(whitespace) {
      whitespace = ((omit["/*"] >> *(char_ - "*/")) > omit["*/"])
        | (omit["//"] >> *(char_ - eol))
        | boost::spirit::ascii::space_type();
    }
  };

  rule<lp_iterator, std::string(), whitespace_grammar> rule
  = (lit("data") > lit('{')) > string("foo") > lit('}');


}

int main() {
  using test::lp_iterator;
  std::string in("data { foo");
  lp_iterator begin = lp_iterator(in.begin());
  lp_iterator end = lp_iterator(in.end());
  test::whitespace_grammar white_gram;
  std::string result;
  try {
    phrase_parse(begin, end, test::rule, white_gram, result);
  } catch (const test::expectation_failure<lp_iterator>& e) {
    std::cout << e.what_ << std::endl;
  }
}

$ ./a.out
"}"

There's a ton of other logic floating around in our grammars, so I'm guessing the error's getting thrown and then ignored by one of the many layers we have in place.

Current Version:

v2.16.0

[mitzimorris]

now that feature #2280 has been merged into develop via PR #2357, given program fragment data {, the parser generates the following error:

PARSER EXPECTED: whitespace to end of file.
FOUND AT line 12: 
data {





make: *** [foo.hpp] Error 253

[mitzimorris]

not a great error message - for that we have issue: #2367

[bob-carpenter]

OK, closing.