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5.21 PLVprs: String Parsing

The PLVprs (PL/Vision PaRSe) package offers a set of programs which provide generic and flexible string parsing capabilities. See Chapter 10, PLVprs, PLVtkn, and PLVprsps: Parsing Strings for details.

5.21.1 Package constants

c_ignore_case CONSTANT VARCHAR2(1) := 'I';
c_respect_case CONSTANT VARCHAR2(1) := 'R';

Use these constants to indicate whether you want case to be ignored or respected in the current operation.

c_all CONSTANT VARCHAR(3) := 'ALL';
c_word CONSTANT VARCHAR(4) := 'WORD';
c_delim CONSTANT VARCHAR(5) := 'DELIM';

The different types of atomics; c_all indicates "all atomics"; c_word indicates "words only"; c_delim indicates "delimiters only".

std_delimiters CONSTANT VARCHAR2 (50) :=
'!@#$%^&*()-_=+\|`~{{]};:''",<.>/?' ||
PLVchr.newline_char || PLVchr.tab_char || PLVchr.space_char;

The standard set of delimiter characters.

plsql_delimiters CONSTANT VARCHAR2 (50) :=
'!@%^&*()-=+\|`~{{]};:''",<.>/?' ||
PLVchr.newline_char || PLVchr.tab_char || PLVchr.space_char;

The set of delimiters for the PL/SQL language; this list is a bit different from the std_delimiters . The underscore and pound sign characters, for example, are not delimiters in PL/SQL .

5.21.2 Wrapping long strings into paragraphs

PROCEDURE wrap
(text_in IN VARCHAR2,
line_length IN INTEGER,
paragraph_out IN OUT PLVtab.vc2000_table,
num_lines_out IN OUT INTEGER);

Wraps the string provided by text_in into separate lines with a maximum specified length, each line of which is stored in consecutive rows in a PL/SQL table.

FUNCTION wrapped_string
(text_in IN VARCHAR2,
line_length IN INTEGER := 80,
prefix_in IN VARCHAR2 := NULL)
RETURN VARCHAR2;

Returns a long string wrapped into a series of lines separated by newline characters. This version of wrap avoids the need to define and manipulate a PL/SQL table.

PROCEDURE display_wrap
(text_in IN VARCHAR2,
line_length IN INTEGER := 80,
prefix_in IN VARCHAR2 := NULL);

Displays the wrapped version of text_in using the p.l procedure (and DBMS_OUTPUT.PUT_LINE).

5.21.3 Analyzing string contents

FUNCTION next_atom_loc
(string_in IN VARCHAR2,
start_loc_in IN NUMBER,
direction_in IN NUMBER := +1,
delimiters_in IN VARCHAR2 := std_delimiters)
RETURN INTEGER;

Returns the location in the string of the next atomic. You provide the starting location of the scan, the direction of the scan (usually +1 or -1, but you can provide other values as well), and the delimiters to be used in the scan.

FUNCTION numatomics
(string_in IN VARCHAR2,
count_type_in IN VARCHAR2 := c_all,
delimiters_in IN VARCHAR2 := std_delimiters)
RETURN INTEGER;

Returns the number of atomics in a string, where the definition of an atomic is provided by the count type (all or word or delimiter) and the set of delimiters.

FUNCTION nth_atomic
(string_in IN VARCHAR2,
nth_in IN NUMBER,
count_type_in IN VARCHAR2 := c_all,
delimiters_in IN VARCHAR2 := std_delimiters)
RETURN VARCHAR2;

Returns the n th atomic in a string, where the definition of an atomic is provided by the count type (all or word or delimiter) and the set of delimiters.

FUNCTION numinstr
(string_in IN VARCHAR2,
substring_in IN VARCHAR2,
ignore_case_in IN VARCHAR2 := c_ignore_case)
RETURN INTEGER;

Returns the number of times a substring occurs in a string. You can choose to perform a search that is case-sensitive or that ignores case.

5.21.4 Parsing strings

PROCEDURE string
(string_in IN VARCHAR2,
atomics_list_out OUT PLVtab.vc2000_table,
num_atomics_out IN OUT NUMBER,
delimiters_in IN VARCHAR2 := std_delimiters);

Parses a string into atomics that are loaded into a PL/SQL table. You decide which characters will serve as the delimiters.

PROCEDURE string
(string_in IN VARCHAR2,
atomics_list_out IN OUT VARCHAR2,
num_atomics_out IN OUT NUMBER,
delimiters_in IN VARCHAR2 := std_delimiters);

Parses a string into atomics stored in a string with each atomic separated by a vertical bar. Once again, you decide which characters will serve as the delimiters.

PROCEDURE display_atomics
(string_in IN VARCHAR2,
delimiters_in IN VARCHAR2 := std_delimiters);

Displays the individual atomics in a string, as defined by the provided list of delimiters.


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