Hi Eric, Thanks for getting back to me. I'm pretty sure this must have something to do with my Boost version (1.49.0). Comments below. On Wed, Jul 23, 2014 at 5:57 PM, Eric Niebler wrote:

On 7/23/2014 3:47 PM, Greg Rubino wrote:

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On Wed, Jul 23, 2014 at 4:07 PM, Greg Rubino wrote:

...

Hi all,

I'm trying to capture a float with xpressive and put it into a local map. As a simplified example, I tried just pushing the matched pattern to a float and the result is always a float containing '0'.

namespace xpr = boost::xpressive;

std::map l_floatOperMap;

xpr::sregex l_relation = xpr::as_xpr("<=") | ">=" | "<" | ">"); l_floatRestriction = !(xpr::s1 = l_relation) >> (xpr::s2 = (+xpr::_d >> '.' >> +xpr::_d)) [xpr::ref(l_floatOperMap)[xpr::as<float>(xpr::s2)] = xpr::asstd::string(xpr::s1)];

However, when I go to print the contents of l_floatOperMap, it contains only the tuple (0, ""). Is it something I'm doing wrong? It seems like this should work to me.

I neglected to mention that I am actually doing the very same thing with uint32_t and it works fine.

Works for me. This program:

#include <map> #include <iostream> #include #include

int main() { namespace xpr = boost::xpressive;

std::map l_floatOperMap;

How did you get away with no #include<string>?

xpr::sregex l_relation = xpr::as_xpr("<=") | ">=" | "<" | ">"; xpr::sregex l_floatRestriction = !(xpr::s1 = l_relation) >> (xpr::s2 = (+xpr::_d >> '.' >> +xpr::_d)) [ xpr::ref(l_floatOperMap)[xpr::as<float>(xpr::s2)] = xpr::asstd::string(xpr::s1) ];

std::string str = ">3.14";

if(xpr::regex_match(str, l_floatRestriction)) { for(auto p : l_floatOperMap)

I'm using c++03, so I have no auto :(

{ std::cout << "(" << p.first << ", " << p.second << ")" << std::endl; } } }

Gives me this expected output:

(3.14, >)

When I compile with gcc 4.8 and Boost 1.55 at home I get the same result, although my program looks more like this: #include <map> #include <string> #include <iostream> #include #include #include namespace xpr = boost::xpressive; int main(int argc, char** argv) { typedef std::map float_oper_map; typedef std::map uint_oper_map; float_oper_map float_map; uint_oper_map uint_map; xpr::sregex relation = xpr::as_xpr("<=") | ">=" | "<" | ">"; xpr::sregex float_restrict = !(xpr::s1 = relation) >> (xpr::s2 = (+xpr::_d >> '.' >> +xpr::_d)) [ xpr::ref(float_map)[xpr::as<float>(xpr::s2)] = xpr::asstd::string(xpr::s1) ]; xpr::sregex uint_restrict = !(xpr::s1 = relation) >> (xpr::s2 = +xpr::_d) [ xpr::ref(uint_map)[xpr::as<unsigned int>(xpr::s2)] = xpr::asstd::string(xpr::s1) ]; xpr::sregex expression = uint_restrict | float_restrict; std::string float_str = ">3.14"; std::string uint_str = ">3"; if(xpr::regex_match(float_str, expression)) { BOOST_FOREACH(const float_oper_map::value_type& val, float_map) { std::cout << '(' << val.first << ',' << val.second << ')' << std::endl; } } if(xpr::regex_match(uint_str, expression)) { BOOST_FOREACH(const uint_oper_map::value_type& val, uint_map) { std::cout << '(' << val.first << ',' << val.second << ')' << std::endl; } } return 0; } // END I'm going to try with Boost 1.49 and see if I get different results. If anything interesting happens, I'll get back on this thread. I should definitely be able to come up with a full repro tomorrow. Thanks again! Greg