CREATE OR REPLACE PACKAGE parse_strings AUTHID DEFINER
IS
SUBTYPE maxvarchar2_t IS VARCHAR2 (32767);
/*
Each of the collection types below correspond to (are returned by)
one of the parse functions.
items_tt - a simple list of strings
nested_items_tt - a list of lists of strings
named_nested_items_tt - a list of named lists of strings
This last type also demonstrates the power and elegance of string-indexed
collections. The name of the list of elements is the index value for
the "outer" collection.
*/
TYPE items_tt IS TABLE OF maxvarchar2_t
INDEX BY PLS_INTEGER;
TYPE nested_items_tt IS TABLE OF items_tt
INDEX BY PLS_INTEGER;
TYPE named_nested_items_tt IS TABLE OF items_tt
INDEX BY maxvarchar2_t;
/*
Parse lists with a single delimiter.
Example: a,b,c,d
Here is an example of using this function:
DECLARE
l_list parse.items_tt;
BEGIN
l_list := parse.string_to_list ('a,b,c,d', ',');
END;
*/
FUNCTION string_to_list (string_in IN VARCHAR2, delim_in IN VARCHAR2)
RETURN items_tt;
/*
Parse lists with nested delimiters.
Example: a,b,c,d|1,2,3|x,y,z
Here is an example of using this function:
DECLARE
l_list parse.nested_items_tt;
BEGIN
l_list := parse.string_to_list ('a,b,c,d|1,2,3,4', '|', ',');
END;
*/
FUNCTION string_to_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
RETURN nested_items_tt;
/*
Parse named lists with nested delimiters.
Example: letters:a,b,c,d|numbers:1,2,3|names:steven,george
Here is an example of using this function:
DECLARE
l_list parse.named_nested_items_tt;
BEGIN
l_list := parse.string_to_list ('letters:a,b,c,d|numbers:1,2,3,4', '|', ':', ',');
END;
*/
FUNCTION string_to_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, name_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
RETURN named_nested_items_tt;
PROCEDURE display_list (string_in IN VARCHAR2
, delim_in IN VARCHAR2:= ','
);
PROCEDURE display_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
);
PROCEDURE display_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, name_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
);
PROCEDURE show_variations;
/* Helper function for automated testing */
FUNCTION nested_eq (list1_in IN items_tt
, list2_in IN items_tt
, nulls_eq_in IN BOOLEAN
)
RETURN BOOLEAN;
END parse_strings; Package created.
CREATE OR REPLACE PACKAGE BODY parse_strings
IS
FUNCTION string_to_list (string_in IN VARCHAR2, delim_in IN VARCHAR2)
RETURN items_tt
IS
c_end_of_list CONSTANT PLS_INTEGER := -99;
l_item maxvarchar2_t;
l_startloc PLS_INTEGER := 1;
items_out items_tt;
PROCEDURE add_item (item_in IN VARCHAR2)
IS
BEGIN
IF item_in = delim_in
THEN
/* We don't put delimiters into the collection. */
NULL;
ELSE
items_out (items_out.COUNT + 1) := item_in;
END IF;
END;
PROCEDURE get_next_item (string_in IN VARCHAR2
, start_location_io IN OUT PLS_INTEGER
, item_out OUT VARCHAR2
)
IS
l_loc PLS_INTEGER;
BEGIN
l_loc := INSTR (string_in, delim_in, start_location_io);
IF l_loc = start_location_io
THEN
/* A null item (two consecutive delimiters) */
item_out := NULL;
ELSIF l_loc = 0
THEN
/* We are at the last item in the list. */
item_out := SUBSTR (string_in, start_location_io);
ELSE
/* Extract the element between the two positions. */
item_out :=
SUBSTR (string_in
, start_location_io
, l_loc - start_location_io
);
END IF;
IF l_loc = 0
THEN
/* If the delimiter was not found, send back indication
that we are at the end of the list. */
start_location_io := c_end_of_list;
ELSE
/* Move the starting point for the INSTR search forward. */
start_location_io := l_loc + 1;
END IF;
END get_next_item;
BEGIN
IF string_in IS NULL OR delim_in IS NULL
THEN
/* Nothing to do except pass back the empty collection. */
NULL;
ELSE
LOOP
get_next_item (string_in, l_startloc, l_item);
add_item (l_item);
EXIT WHEN l_startloc = c_end_of_list;
END LOOP;
END IF;
RETURN items_out;
END string_to_list;
FUNCTION string_to_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
RETURN nested_items_tt
IS
l_elements items_tt;
l_return nested_items_tt;
BEGIN
/* Separate out the different lists. */
l_elements := string_to_list (string_in, outer_delim_in);
/* For each list, parse out the separate items
and add them to the end of the list of items
for that list. */
FOR indx IN 1 .. l_elements.COUNT
LOOP
l_return (l_return.COUNT + 1) :=
string_to_list (l_elements (indx), inner_delim_in);
END LOOP;
RETURN l_return;
END string_to_list;
FUNCTION string_to_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, name_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
RETURN named_nested_items_tt
IS
c_name_position constant pls_integer := 1;
c_items_position constant pls_integer := 2;
l_elements items_tt;
l_name_and_values items_tt;
l_return named_nested_items_tt;
BEGIN
/* Separate out the different lists. */
l_elements := string_to_list (string_in, outer_delim_in);
FOR indx IN 1 .. l_elements.COUNT
LOOP
/* Extract the name and the list of items that go with
the name. This collection always has just two elements:
index 1 - the name
index 2 - the list of values
*/
l_name_and_values :=
string_to_list (l_elements (indx), name_delim_in);
/*
Use the name as the index value for this list.
*/
l_return (l_name_and_values (c_name_position)) :=
string_to_list (l_name_and_values (c_items_position), inner_delim_in);
END LOOP;
RETURN l_return;
END string_to_list;
PROCEDURE display_list (string_in IN VARCHAR2
, delim_in IN VARCHAR2:= ','
)
IS
l_items items_tt;
BEGIN
DBMS_OUTPUT.put_line (
'Parse "' || string_in || '" using "' || delim_in || '"'
);
l_items := string_to_list (string_in, delim_in);
FOR indx IN 1 .. l_items.COUNT
LOOP
DBMS_OUTPUT.put_line ('> ' || indx || ' = ' || l_items (indx));
END LOOP;
END display_list;
PROCEDURE display_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
IS
l_items nested_items_tt;
BEGIN
DBMS_OUTPUT.put_line( 'Parse "'
|| string_in
|| '" using "'
|| outer_delim_in
|| '-'
|| inner_delim_in
|| '"');
l_items := string_to_list (string_in, outer_delim_in, inner_delim_in);
FOR outer_index IN 1 .. l_items.COUNT
LOOP
DBMS_OUTPUT.put_line( 'List '
|| outer_index
|| ' contains '
|| l_items (outer_index).COUNT
|| ' elements');
FOR inner_index IN 1 .. l_items (outer_index).COUNT
LOOP
DBMS_OUTPUT.put_line( '> Value '
|| inner_index
|| ' = '
|| l_items (outer_index) (inner_index));
END LOOP;
END LOOP;
END display_list;
PROCEDURE display_list (string_in IN VARCHAR2
, outer_delim_in IN VARCHAR2
, name_delim_in IN VARCHAR2
, inner_delim_in IN VARCHAR2
)
IS
l_items named_nested_items_tt;
l_index maxvarchar2_t;
BEGIN
DBMS_OUTPUT.put_line( 'Parse "'
|| string_in
|| '" using "'
|| outer_delim_in
|| '-'
|| name_delim_in
|| '-'
|| inner_delim_in
|| '"');
l_items :=
string_to_list (string_in
, outer_delim_in
, name_delim_in
, inner_delim_in
);
l_index := l_items.FIRST;
WHILE (l_index IS NOT NULL)
LOOP
DBMS_OUTPUT.put_line( 'List "'
|| l_index
|| '" contains '
|| l_items (l_index).COUNT
|| ' elements');
FOR inner_index IN 1 .. l_items (l_index).COUNT
LOOP
DBMS_OUTPUT.put_line( '> Value '
|| inner_index
|| ' = '
|| l_items (l_index) (inner_index));
END LOOP;
l_index := l_items.NEXT (l_index);
END LOOP;
END display_list;
PROCEDURE show_variations
IS
PROCEDURE show_header (title_in IN VARCHAR2)
IS
BEGIN
DBMS_OUTPUT.put_line (RPAD ('=', 60, '='));
DBMS_OUTPUT.put_line (title_in);
DBMS_OUTPUT.put_line (RPAD ('=', 60, '='));
END show_header;
BEGIN
show_header ('Single Delimiter Lists');
display_list ('a,b,c');
display_list ('a;b;c', ';');
display_list ('a,,b,c');
display_list (',,b,c,,');
show_header ('Nested Lists');
display_list ('a,b,c,d|1,2,3|x,y,z', '|', ',');
show_header ('Named, Nested Lists');
display_list ('letters:a,b,c,d|numbers:1,2,3|names:steven,george'
, '|'
, ':'
, ','
);
END;
FUNCTION nested_eq (list1_in IN items_tt
, list2_in IN items_tt
, nulls_eq_in IN BOOLEAN
)
RETURN BOOLEAN
IS
l_return BOOLEAN := list1_in.COUNT = list2_in.COUNT;
l_index PLS_INTEGER := 1;
BEGIN
WHILE (l_return AND l_index IS NOT NULL)
LOOP
l_return := list1_in (l_index) = list2_in (l_index);
l_index := list1_in.NEXT (l_index);
END LOOP;
RETURN l_return;
EXCEPTION
WHEN NO_DATA_FOUND
THEN
RETURN FALSE;
END nested_eq;
END parse_strings; Package Body created.