Method ADT.CircularList()->replace_front()

Method replace_front

ValueType|zero replace_front(ValueType value)

Description

Replace a value to the front of the list.

Parameter value

The value to add.

Returns

Returns the element that was at the back of the list if it was full, and UNDEFINED otherwise.

This operation is similar to:

mixed replace_front(mixed value)
    {
      mixed ret = UNDEFINED;
      if (sizeof(this) == max_size()) {
        ret = pop_back();
      }
      push_front(value);
      return ret;
    }

Note

Presence of this function is indicated by __HAVE_CIRCULAR_LIST_REPLACE_FRONT__.