# Container objects

This chapter is a reference of the reserved container objects with their respective builtin methods. Some of these container objects are iterable objects. When an object is iterable, an iterator constructor constructor is provided. The `iterable-p` predicate returns true if the container is an iterable object. The `iterator` method can be used to construct an object iterator. For a given iterator, the predicates `end-p` and `valid-p` can be used to check for the end or a valid iterator position. The `next` method move the iterator to its next position. The `prev` method move the iterator -- if possible -- to its previous position. The `get-object` method returns the object at the current iterator position.