Rules have the following syntax:
(defrule [<module-name>::]<symbol-name>
[<string-comment>]
[(declare [(auto-focus <boolean-expression>])|
[(salience <integer-expression>)]|
[(oneshot <boolean-expression>])|
[(enabled <boolean-expression>])]
<conditional-element>*
=>
<action>*)
<conditional-element> = <pattern> | ?<variable-name> <- <pattern> |
(test <function-call>) |
(not <conditional-element>) |
(unique <conditional-element>) |
(explicit <conditional-element>) |
(exists <conditional-element>+)
<pattern> = (<template-name> <slot>*)
<slot> = (<slot-name> <constraint>*)
<constraint> = ? | $? | <connected-constraint>
<connected-constraint> = <single-constraint> | <<single-constraint>&<connected-constraint>> |
<<single-constraint>|<connected-constraint>>
<single-constraint> = <constant> | <variable> | :<function-call> | =<function-call> |
~<constant> | ~<variable> | ~:<function-call> | ~=<function-call>
<action> = <constant>|<variable>|<function-call>
:: = Module separator. Module name is optional. If not specified, a rule belongs to the currently active module
Note: Brackets ([) and (]) define optional elements of the construct. The (|) character defines an or condition. An asterisk (*) defines zero or more of the preceding element (or disjunction of elements). A plus sign (+) defines one or more of the preceding element.
Valid Rule Definitions
Assuming the following fact templates:
(deftemplate employee (slot name) (slot company) (slot salary (type float)) (slot position) (slot yearsofservice (type integer)))
(deftemplate benefits (slot name) (multislot awards) (multislot raises))
valid rules are:
(defrule five-year-raise
"automatic five year raise"
(declare (salience 0))
?employee1 <- (employee (name ?name1) (salary ?salary1) (yearsofservice ?yearsofservice1&:(> ?yearsofservice1 5)) )
(not (benefits (name ?name1) (raises 5-year) ))
=>
(assert (benefits (name ?name1) (raises 5-year)))
(modify ?employee1 (salary (* ?salary1 1.1))))
(defrule Printout-all-programmers
"list all programmers"
(declare (salience 0))
?employee <- (employee (position "Programmer") )
=>
(printout t ?employee))
