Method operator ++

unittests/catch.hpp:5371–5386

            }

            auto operator ++() -> iterator& {
                m_pos += m_len;
                if( m_pos < line().size() && line()[m_pos] == '\n' )
                    m_pos += 1;
                else
                    while( m_pos < line().size() && isWhitespace( line()[m_pos] ) )
                        ++m_pos;

                if( m_pos == line().size() ) {
                    m_pos = 0;
                    ++m_stringIndex;
                }
                if( m_stringIndex < m_column.m_strings.size() )
                    calcLength();
                return *this;
            }
            auto operator ++(int) -> iterator {
                iterator prev( *this );
                operator++();