A pattern of literal and special characters that describes a set of character strings. The use of regular
expressions in text searches locates one or more occurrences of the character strings represented by
the expression. A search using a regular expression is more powerful than a search for a simple character
string, since the regular expression represents a greater (potentially infinite) number of character
strings and searches for them in parallel. In ABAP, regular expressions can be used in the statements
REPLACE, as arguments in certain
built-in functions, and in the classes CL_ABAP_REGEX and CL_ABAP_MATCHER.