Chapter 5 PL/Vision Package Specifications |
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 for details.
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.
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.
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.
FUNCTION nitems (stack_in IN VARCHAR2 := defstk)
RETURN INTEGER;
Returns the number of items currently in the stack.
FUNCTION itemin (stack_in IN VARCHAR2, item_in IN VARCHAR2)
RETURN BOOLEAN;
Returns TRUE if the specified item is found in the stack.
PROCEDURE show
(stack_in IN VARCHAR2 := defstk,
show_contents_in IN BOOLEAN := FALSE);
Requests that pre-action status of stack be displayed for the specified stack (or all).
PROCEDURE noshow;
Turns off display of pre-action status.
FUNCTION showing RETURN BOOLEAN;
Returns TRUE if showing pre-action status.
PROCEDURE verify
(stack_in IN VARCHAR2 := defstk,
show_contents_in IN BOOLEAN := FALSE);
Requests that post-action status of stack be displayed for the specified stack (or all).
PROCEDURE noverify;
Turns off display of post-action status.
FUNCTION verifying RETURN BOOLEAN;
Returns TRUE if showing post-action status.
5.23 PLVrb: Rollback Processing | 5.25 PLVtab: Table Interface |
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