dindexer/include/helpers/infix_iterator.hpp

// see http://stackoverflow.com/questions/3496982/printing-lists-with-commas-c/3497021#3497021
// infix_iterator.h
//
// Lifted from Jerry Coffin's 's prefix_ostream_iterator
#if !defined(INFIX_ITERATOR_H_)
#define  INFIX_ITERATOR_H_
#include <ostream>
#include <iterator>
template <class T,
          class charT=char,
          class traits=std::char_traits<charT> >
class infix_ostream_iterator :
    public std::iterator<std::output_iterator_tag,void,void,void,void>
{
    std::basic_ostream<charT,traits> *os;
    charT const* delimiter;
    bool first_elem;
public:
    typedef charT char_type;
    typedef traits traits_type;
    typedef std::basic_ostream<charT,traits> ostream_type;
    infix_ostream_iterator(ostream_type& s)
        : os(&s),delimiter(0), first_elem(true)
    {}
    infix_ostream_iterator(ostream_type& s, charT const *d)
        : os(&s),delimiter(d), first_elem(true)
    {}
    infix_ostream_iterator<T,charT,traits>& operator=(T const &item)
    {
        // Here's the only real change from ostream_iterator:
        // Normally, the '*os << item;' would come before the 'if'.
        if (!first_elem && delimiter != 0)
            *os << delimiter;
        *os << item;
        first_elem = false;
        return *this;
    }
    infix_ostream_iterator<T,charT,traits> &operator*() {
        return *this;
    }
    infix_ostream_iterator<T,charT,traits> &operator++() {
        return *this;
    }
    infix_ostream_iterator<T,charT,traits> &operator++(int) {
        return *this;
    }
};
#endif