The following rule adds quotation marks to a string that is passed to MESSAGE. The quotation marks are needed for the third argument because MESSAGE uses
TOKEN to separate the tokens in this argument. Each token is used to substitute for a percent sign (%) in the message in the MESSAGES table. Message number 2 in the TABLE table instance is: At %.
By putting quotation marks around the string, it becomes a quoted string. TOKEN treats a quoted string as one token, and so the entire string substitutes for the percent sign.