Built-In Functions table

Last Updated : Sep 01, 2026 |
Prolog information
Variable
Valid Forms
Description
exists()
exists(%HEADERS[“Header”])
Returns “TRUE” or “FALSE” based on the existence of a header, or a param in the message.
exists(%HEADERS[“Header”].PARAMS[“Param”])
remove()
remove(%HEADERS[“Header”])
Removes a header or a parameter from the message.
remove(%HEADERS[“Header”].PARAMS[“Param”])
regex_match()
%HEADERS[“Header”].regex_match(“regex”)
Returns “TRUE” or “FALSE” based on whether the regular expression found a match in the text or not.
%HEADERS[“Header”].PARAMS[“Param”].regex_match(“regex”)
regex_get()
%HEADERS[“Header”].regex_get(“regex”)
Returns the extracted string by the regular expression. The return value will be an empty string if no match was found.
%HEADERS[“Header”].PARAMS[“Param”].regex_get(“regex”)
regex_replace()
HEADERS[“Header”].regex_replace(“regex”, “string”)
Replaces a given match with the provided string within the header string or a param.
%HEADERS[“Header”].PARAMS[“Param”].regex_replace(“regex”, “string”)