2011/5/2 alfC <alfredo.correa@gmail.com>
Hi,
Does Phoenix support conditional expression? I know if supports if_
*statements* but it seems that there's is no conditional (expression*.
The question what is is the equivalent for
"(x>2.)?(1.):(-1.)"
in general. For example, I tryed with if_[].else_[] hoping that the
statement is used as result but with no luck:
#include<boost/phoenix/phoenix.hpp>
#include<iostream>
using namespace boost::phoenix;
using namespace boost::phoenix::arg_names;
int main(){
std::clog << (arg1*arg1)(2.) << std::endl; //returns correctly 4
std::clog <<
(if_(arg1>2.)[val(1.)].else_[val(-1.)])(2.)
<< std::endl; //syntax error
return 0;
}
The syntax error points that the expression fails to evaluate as a
number. Any ideas? -- Thanks, Alfredo
See:
simply:
std::clog << if_else(arg1>2., 1., -1.)(2.) << std::endl;
HTH