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
predefined functions, and in the classes CL_ABAP_REGEX and CL_ABAP_MATCHER.