Noel Huebers wrote
(defquery searchcontext
(declare (variables ?name ?task ?val))
(context
(username ?name)
(action "Bewertet")
(task ?task)
(value ?val)))
Now I want to delete the some facts. How do I get a fact from the
queryresult '?result' ?
;(deffunction delformerattempts(?n ?t ?v)
; (bind ?results (run-query* searchcontext ?n ?t ?v))
; (while (?results next))
; (retract ?results get))
All you have to do is extend the pattern in the query with a binding for
the entire fact:
(defquery searchcontext
(declare (variables ?name ?task ?val))
?context <- (context
(username ?name)
(action "Bewertet")
(task ?task)
(value ?val)))
And then you access it with the get method:
(deffunction delformerattempts (?n ?t ?v)
(bind ?results (run-query* searchcontext ?n ?t ?v))
(while (?results next)
(retract (?results get context ))))
But wouldn't it be more convenient to rearrange things so that the
context fact maintains a counter, with new "Bewertet" events being
counted right there. Here's how:
(clear)
(deftemplate Base (slot username)(slot action)(slot value)(slot task))
(deftemplate Context extends Base (slot count (default 1)))
(deftemplate Event extends Base (slot stamp ))
(defrule IncrementCount
?event <- (Event (username ?s)(action "Bewertet")(value ?v)(task ?t))
?context <- (Context (username ?s)(action "Bewertet")(value ?v)(task
?t)(count ?c))
=>
(modify ?context (count (++ ?c)))
(retract ?event)
)
(defrule FirstTime
?event <- (Event (username ?s)(action "Bewertet")(value ?v)(task ?t))
(not (Context (username ?s)(action "Bewertet")(value ?v)(task ?t)))
=>
(assert (Context (username ?s)(action "Bewertet")(value ?v)(task ?t)))
(retract ?event)
)
(deffacts ecs
(Event (username "Max")(action "Bewertet")(value "3")(task
"Thesis")(stamp 1))
(Event (username "Max")(action "Bewertet")(value "3")(task
"Thesis")(stamp 2))
(Event (username "Max")(action "Bewertet")(value "3")(task
"Thesis")(stamp 3))
)
(reset)
(run)
kr
Wolfgang
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