Re: [Boost-users] [spirit][qi] Iteration / string iterator

On Fri, Oct 1, 2010 at 2:34 PM, alfC wrote:

...

can anybody explain to me why this example from the Spirit.Qi manual works

http://www.boost.org/doc/libs/1_44_0/libs/spirit/example/qi/complex_nu mber.cpp

and when I try to use the string iterators directly I get a horrific compiler error? Something to do with string iterators being pointers or something?

std::string s = "(2, 3)"; // < line added to example bool r = phrase_parse(s.begin(), s.end(), //< only line changed in the example was (first, last)

You are using GCC, phrase_parse's first parameter must be non-const.

Visual studio can accept a const in a non-const if it is a temporary, as above. GCC however, follows the standard, meaning that you must create an iterator for at least the s.begin() and pass the iterator in, not a temporary, meaning change the above lines to this:

std::string s = "(2, 3)"; // < line added to example std::string::iterator iter = s.begin(); bool r = phrase_parse(iter, s.end(), //< only line changed in the example was (first, last)

Starting with V2.4 (Boost V1.44) Spirit has a set of overloaded API functions allowing to pass a const iterator as the first parameter as well. Your code would work there just fine. Regards Hartmut --------------- http://boost-spirit.com