(undocumented?) Restrictions on the 'not' conditional element

[Lode Hoste]

Hi all,

I'm wondering why the 'not' conditional behaves different than
expected. For instance:

(defrule hello
(not (> (+ 1 1) 1))
=>
(printout t "123"))

is an invalid rule. It gives a syntax error at the open brackets for
the + operator.
Another parsing problem is found in the following definition:

(defrule hello
(not (= 1 1))
=>
(printout t "123"))

Note that the following examples do work:

(defrule hello
(not (> 1 1))
=>
(printout t "123"))

(defrule hello
(not (eq 1 1))
=>
(printout t "123"))

Is there a specific reason why these (arithmetic?) limitations are imposed?

Greetings,

Lode

[CLIPS Support]

You need to use the test condition element if you want to evaluate an
expression on the condition side of a rule.

(defrule hello
(test (not (> (+ 1 1) 1)))

=>
(printout t "123"))

[Lode Hoste]

Sorry, I simplified my question (way) too much.

I'm trying to compose a negation condition with fact matching and test
functions.
My invalid rule:

(deftemplate Foo (slot bar))
(deffunction complexFunction (?a ?b) FALSE)

(defrule hello
(Foo (bar ?a))
(not (Foo (bar ?b))
(test (complexFunction ?a ?b)))

=>
(printout t "123"))

The alternative (although harder to read) does work:

(defrule hello2
(Foo (bar ?a))
(not (Foo (bar ?b&:(complexFunction ?a ?b))))

=>
(printout t "123"))

Is there a reason for this limitation?

Thank you

2011/8/5 CLIPS Support <gdronl...@swbell.net>:

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[CLIPS Support]

(defrule hello
(Foo (bar ?a))

(not (and (Foo (bar ?b))
(test (complexFunction ?a ?b))))

=>
(printout t "123"))

On Aug 12, 9:29 am, Lode Hoste <zill...@gmail.com> wrote:
> Sorry, I simplified my question (way) too much.
>
> I'm trying to compose a negation condition with fact matching and test
> functions.
> My invalid rule:
>
> (deftemplate Foo (slot bar))
> (deffunction complexFunction (?a ?b) FALSE)
>
> (defrule hello
>   (Foo (bar ?a))
>   (not (Foo (bar ?b))
>          (test (complexFunction ?a ?b)))
>   =>
>   (printout t "123"))
>
> The alternative (although harder to read) does work:
>
> (defrule hello2
>   (Foo (bar ?a))
>   (not (Foo (bar ?b&:(complexFunction ?a ?b))))
>   =>
>   (printout t "123"))
>
> Is there a reason for this limitation?
>
> Thank you
>

> 2011/8/5 CLIPS Support <gdronline2...@swbell.net>:

> > For more options, visit this group athttp://groups.google.com/group/CLIPSESG?hl=en

>
> > --> IF YOU NO LONGER WANT TO RECEIVE EMAIL <--

> > Visit this group athttp://groups.google.com/group/CLIPSESG?hl=en

> > Click on "Edit my membership" link.
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> > Click the "Save these settings" button.
>
> > --> IF YOU WANT TO UNSUBSCRIBE <--

> > Visit this group athttp://groups.google.com/group/CLIPSESG?hl=en

[Lode Hoste]

Hi,

I'm reviving this thread since I finally found some time to figure out the problematic conditions.

It seems that adding a test CE after a 'complex' not node, results in rules not getting matched:

(deftemplate Event (slot value) (slot time))

(defrule example-working

  (Event (value 1) (time ?t1))

  (Event (value 1) (time ?t2))

  (test (< ?t1 ?t2))

  (test (< ?t1 ?t2))

  (not (and (Event (value 0) (time ?tn))

            (test (< ?t1 ?tn))))

 =>

  (printout t "Works 1" crlf)

)

(defrule example-failing-1

  (Event (value 1) (time ?t1))

  (Event (value 1) (time ?t2))

  (test (< ?t1 ?t2))

  (not (and (Event (value 0) (time ?tn))

            (test (< ?t1 ?tn))))

  (test (< ?t1 ?t2))

=>

 (printout t "Fails 1" crlf)

)

(defrule example-simple-working-2

  (Event (value 1) (time ?t1))

  (Event (value 1) (time ?t2))

  (test (< ?t1 ?t2))

  (not (Event (value 0) (time ?tn)))

  (test (< ?t1 ?t2))

=>

 (printout t "Works (Simple!) 2" crlf)

)

(defrule example-failing-2

  (Event (value 1) (time ?t1))

  (Event (value 1) (time ?t2))

  (not (and (Event (value 0) (time ?tn))

            (test (< ?t1 ?tn))))

  (test (< ?t1 ?t2))

  (test (< ?t1 ?t2))

=>

 (printout t "Fails 2" crlf)

)

(defrule example-working-3

  (Event (value 1) (time ?t1))

  (not (and (Event (value 0) (time ?tn))

            (test (< ?t1 ?tn))))

  (Event (value 1) (time ?t2))

  (test (< ?t1 ?t2))

  (test (< ?t1 ?t2))

=>

 (printout t "Works 3" crlf)

)

(assert (Event (value 1) (time 0)))

(assert (Event (value 1) (time 1)))

I hope this notice will be helpful for some people.

2011/8/14 CLIPS Support <gdronl...@swbell.net>

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