int can_put_and_get(str)
string str;

Define this function if you want to make it possible to put something
into current object.

Return true if ok, otherwise 0. That means that default is that it is not
possible to put something into an object.

When a player does "look at xxx", then "xxx" will be sent to can_put_and_get(),
to test if the player can look at the inventory. Otherwise, 'str' will be 0.

This is trivial for containers. If the are open, they return 1.

If id() accepts other things, like "lock" (in a chest for example).
Then "lock" will be sent to can_put_and_get(), which should return false,
because the lock has no inventory (of course).

See also lfun/id(), lfun/long().