A distributed action is a user-defined expression evaluated for each instance-set which satisfies a query. Unlike queries, distributed actions must use messages to read slots of instance-set members. If more than one action is required, use the progn function (see section 12.6.5) to group them.
Action Syntax
<action> ::= <expression>
Example
Continuing the previous example, one distributed action might be to simply print out the ordered pair to the screen.
(printout t "(" ?man-or-boy "," ?woman-or-girl ")" crlf)