5.6. PLVchr: Operations on Single Characters
The PLVchr (PL/Vision CHaRacter) package provides information about single characters in a string. See the companion disk for details (view disk content online at http://examples.oreilly.com/advoracle).
5.6.1. PLVchr constants
blank_char CONSTANT CHAR(1) := ' '; space_char CONSTANT CHAR(1) := ' '; quote1_char CONSTANT CHAR(1) := ''''; quote2_char CONSTANT CHAR(2) := ''''''; tab_char CONSTANT CHAR(1) := CHR(9); newline_char CONSTANT CHAR(1) := CHR(10);
Named constants to use in place of hard-coded literals. Sure, there is more typing involved. But at least you don't have to mess with single quotes, and the code is a lot more readable.
c_nonprinting CONSTANT CHAR(1) := 'n'; c_digit CONSTANT CHAR(1) := '9'; c_letter CONSTANT CHAR(1) := 'a'; c_other CONSTANT CHAR(1) := '*'; c_all CONSTANT CHAR(1) := '%';
Action codes for use in PLVchr programs that allow you to specify the category of character that you want to work with.
5.6.2. Character type functions
FUNCTION is_quote (char_in IN VARCHAR2) RETURN BOOLEAN; FUNCTION is_blank (char_in IN VARCHAR2) RETURN BOOLEAN;
Functions to encapsulate hard-coded checks for contents of the strings.
FUNCTION is_nonprinting (code_in IN INTEGER) RETURN BOOLEAN; FUNCTION is_nonprinting (letter_in IN VARCHAR2) RETURN BOOLEAN;
Returns TRUE if the character (or, overloaded as this function is, the ASCII code) is a non-printing character.
FUNCTION is_digit (code_in IN INTEGER) RETURN BOOLEAN; FUNCTION ...