// stack_iterator guarantees validity so long as you don't manually
// mess with item_def.link: i.e., you can kill the item you're
// examining but you can't kill the item linked to it.
class stack_iterator : public std::iterator<std::forward_iterator_tag,
                                            item_def>
{
public:
    stack_iterator( const coord_def& pos );
    stack_iterator( int start_link );
    operator bool() const;
    item_def& operator *() const;
    int link() const;
    const stack_iterator& operator ++ ();
    stack_iterator operator ++ (int);
private:
    int cur_link;
    int next_link;
};

stack_iterator::stack_iterator(const coord_def& pos)
{
    cur_link = igrd(pos);
    if ( cur_link != NON_ITEM )
        next_link = mitm[cur_link].link;
    else
        next_link = NON_ITEM;
}
stack_iterator::stack_iterator(int start_link)
{
    cur_link = start_link;
    if ( cur_link != NON_ITEM )
        next_link = mitm[cur_link].link;
    else
        next_link = NON_ITEM;
}
stack_iterator::operator bool() const
{
    return ( cur_link != NON_ITEM );
}
item_def& stack_iterator::operator*() const
{
    ASSERT( cur_link != NON_ITEM );
    return mitm[cur_link];
}
int stack_iterator::link() const
{
    return cur_link;
}
const stack_iterator& stack_iterator::operator ++ ()
{
    cur_link = next_link;
    if ( cur_link != NON_ITEM )
        next_link = mitm[cur_link].link;
    return *this;
}
stack_iterator stack_iterator::operator++(int dummy)
{
    const stack_iterator copy = *this;
    ++(*this);
    return copy;
}

    int i = igrd[you.x_pos][you.y_pos];
    while (i != NON_ITEM)

    for ( stack_iterator si(you.pos()); si; ++si )

        const int next = mitm[i].link;  // In case we can't get it later.
        if (mitm[i].base_type != OBJ_WEAPONS
                && mitm[i].base_type != OBJ_MISSILES
            || item_is_stationary(mitm[i])) // Held in a net?

        item_def& item(*si);
        if ( (item.base_type != OBJ_WEAPONS
              && item.base_type != OBJ_MISSILES)
             || item_is_stationary(item)) // Held in a net?

            i = next;

        if (!check_warning_inscriptions(mitm[i], OPER_DESTROY))

        if (!check_warning_inscriptions(item, OPER_DESTROY))

            i = next;

        const int value = item_value( mitm[i], true );

        const int value = item_value( item, true );

        bool is_evil_weapon = is_evil_item(mitm[i]);
        if (is_evil_weapon
            || _destroyed_valuable_weapon(value, mitm[i].base_type))

        const bool is_evil_weapon = is_evil_item(item);
        if (is_evil_weapon || _destroyed_valuable_weapon(value, item.base_type))

        _print_sacrifice_message(GOD_ELYVILON, mitm[i], pgain);

        _print_sacrifice_message(GOD_ELYVILON, item, pgain);

        destroy_item(i);

        destroy_item( si.link() );

        i = next;