| 1 | #include <boost/spirit/include/qi.hpp>
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| 2 | #include <boost/spirit/include/phoenix_operator.hpp>
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| 3 |
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| 4 | namespace qi = boost::spirit::qi;
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| 5 |
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| 6 | template <typename P, typename T>
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| 7 | void test_parser_attr(char const* input, P const& p, T& attr, bool full_match = true)
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| 8 | {
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| 9 | using boost::spirit::qi::parse;
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| 10 |
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| 11 | char const* f(input);
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| 12 | char const* l(f + strlen(f));
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| 13 | if (parse(f, l, p, attr) && (!full_match || (f == l)))
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| 14 | std::cout << "ok" << std::endl;
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| 15 | else
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| 16 | std::cout << "fail" << std::endl;
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| 17 | }
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| 18 |
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| 19 | /* This test structure represents a primitive range limited type. */
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| 20 | struct body_temp
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| 21 | {
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| 22 | float t;
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| 23 | };
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| 24 |
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| 25 | bool no_chance(false);
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| 26 |
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| 27 | namespace boost { namespace spirit { namespace traits
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| 28 | {
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| 29 | template <>
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| 30 | struct transform_attribute<body_temp, float, qi::domain>
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| 31 | {
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| 32 | typedef float type;
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| 33 | static float pre(body_temp t) { return t.t; }
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| 34 | /* if parsed attribute is within desired range, than assign it,
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| 35 | * otherwise report failure.
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| 36 | */
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| 37 | static bool post(body_temp& t, float const &attr)
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| 38 | {
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| 39 | if (attr > 30.0 && attr < 45.0) {
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| 40 | t.t = attr;
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| 41 | return true;
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| 42 | }
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| 43 | else
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| 44 | return false;
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| 45 | }
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| 46 | static void fail(body_temp &t) { }
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| 47 | };
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| 48 | }}}
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| 49 |
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| 50 | int main(int argc, char **argv)
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| 51 | {
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| 52 | namespace qi = boost::spirit::qi;
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| 53 | using qi::float_;
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| 54 | using qi::omit;
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| 55 | using qi::rule;
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| 56 | using qi::attr_cast;
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| 57 | using boost::phoenix::ref;
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| 58 |
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| 59 | body_temp d1 = { 36.6 }, d2 = { 36.6 };
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| 60 |
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| 61 | rule<char const *, body_temp()> r;
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| 62 |
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| 63 | /* Adapt qi::float_ parser to struct body_temp which represents a range
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| 64 | * limited numeric type. If range can not be accomodated, per conversion
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| 65 | * defined, the first alternative will fail, and second will be invoked,
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| 66 | * to set the error flag.
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| 67 | */
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| 68 | r %= attr_cast<body_temp>(float_) | omit[float_[ref(no_chance) = true]];
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| 69 |
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| 70 | /* Supplied value is within range and will be parsed as appropriate
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| 71 | * range limited float.
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| 72 | */
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| 73 | test_parser_attr("40.0", r, d1);
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| 74 | std::cout << "parsed temp " << d1.t << " error flag " << no_chance
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| 75 | << std::endl;
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| 76 |
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| 77 | no_chance = false;
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| 78 | /* Supplied value is not within allowed range, the parser will take the
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| 79 | * alternative choice to set the error flag.
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| 80 | */
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| 81 | test_parser_attr("20.0", r, d2);
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| 82 | std::cout << "parsed temp " << d2.t << " error flag " << no_chance
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| 83 | << std::endl;
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| 84 |
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| 85 | return 0;
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| 86 | }
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