5.24. PLVstk: Stack Manager
The PLVstk (PL/Vision STacK manager) package is a generic manager for both first-in-first-out (FIFO) and last-in-last-out (LIFO) stacks; it is built on PLVlst. See the companion disk (see http://examples.oreilly.com/advoracle) for details.
5.24.1. Package constants
defstk CONSTANT VARCHAR2(5) := 'stack';
The name of the default stack.
lifo CONSTANT VARCHAR2(4) := 'LIFO';
Indicates that you are working with a last-in-first-out stack. Used in calls to pop.
fifo CONSTANT VARCHAR2(4) := 'FIFO';
Indicates that you are working with a first-in-first-out stack. Used in calls to pop.
5.24.2. Creating and destroying stacks
PROCEDURE make (stack_in IN VARCHAR2 := defstk, overwrite_in IN BOOLEAN := TRUE);
Allocates storage for a stack of up to 1,000 items with the specified name. By default, if the stack already exists it will be reinitialized to an empty stack.
PROCEDURE destroy (stack_in IN VARCHAR2 := defstk);
Releases all memory associated with this stack.
5.24.3. Modifying stack contents
PROCEDURE push (item_in IN VARCHAR2, stack_in IN VARCHAR2 := defstk);
Pushes an item onto the specified stack.
PROCEDURE pop (value_out IN OUT VARCHAR2, stack_in IN VARCHAR2 := defstk, stack_type_in IN VARCHAR2 := lifo);
Pops an item off the top (LIFO) or bottom (FIFO) of the stack.
5.24.4. Analyzing stack contents
FUNCTION nitems (stack_in IN VARCHAR2 := defstk) RETURN INTEGER;
Returns the number of items currently in the stack.
FUNCTION itemin (stack_in ...
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