Differences

This shows you the differences between two versions of the page.

@@ Line 1: / Line 1: @@
+<HTML>
+<HEAD>
+<META HTTP-EQUIV="Content-Type" Content="text/html; charset=Windows-1252">
+<TITLE>DEFRULE</TITLE>
+</HEAD>
+<BODY BGCOLOR="#FFFFFF" TEXT="#000000">
+<OBJECT TYPE="application/x-oleobject" CLASSID="clsid:1e2a7bd0-dab9-11d0-b93a-00c04fc99f9e">
+	<PARAM NAME="Keyword" VALUE="DEFRULE">
+</OBJECT>
+<H1><A NAME="defrule"></A>DEFRULE</H1>
+<P>One of the primary methods of representing knowledge in CLIPS is a rule.  </P>
+<P>A rule is a collection of conditions and the actions to be taken if the </P>
+<P>conditions are met.  The developer of an expert system defines the rules </P>
+<P>which describe how to solve a problem.  Rules execute (or fire) based on </P>
+<P>the existence or non-existence of facts.  CLIPS provides the mechanism </P>
+<P>(the inference engine) which attempts to match the rules to the current </P>
+<P>state of the system (as represented by the fact-list) and applies the </P>
+<P>actions.  </P>
+<PRE><CODE>(defrule &lt;rule-name&gt; [&lt;comment&gt;]
+    [&lt;declaration&gt;]
+    &lt;conditional-element&gt;*
+=&gt;
+    &lt;action&gt;*)
+</CODE></PRE>
+<P><B><U>DECLARATIONS</U></B></P>
+<PRE><CODE>&lt;declaration&gt;           ::= (declare &lt;rule-property&gt;+)
+&lt;rule-property&gt;         ::= (salience &lt;integer-expression&gt;) |
+                            (auto-focus &lt;boolean-symbol&gt;)
+</CODE></PRE>
+<P><B><U>CONDITIONAL ELEMENTS</U></B></P>
+<PRE><CODE>&lt;conditional-element&gt;   ::= &lt;pattern-CE&gt; | &lt;assigned-pattern-CE&gt; |
+                            &lt;not-CE&gt; | &lt;and-CE&gt; | &lt;or-CE&gt; |
+                            &lt;logical-CE&gt; | &lt;test-CE&gt; |
+                            &lt;exists-CE&gt; | &lt;forall-CE&gt;
+&lt;test-CE&gt;               ::= (test &lt;function-call&gt;)
+&lt;not-CE&gt;                ::= (not &lt;conditional-element&gt;)
+&lt;and-CE&gt;                ::= (and &lt;conditional-element&gt;+)
+&lt;or-CE&gt;                 ::= (or &lt;conditional-element&gt;+)
+&lt;exists-CE&gt;             ::= (exists &lt;conditional-element&gt;+)
+&lt;forall-CE&gt;             ::= (forall &lt;conditional-element&gt;
+                                    &lt;conditional-element&gt;+)
+&lt;logical-CE&gt;            ::= (logical &lt;conditional-element&gt;+)
+</CODE></PRE>
+<P><B><U>PATTERN CONDITIONAL ELEMENT</U></B></P>
+<PRE><CODE>&lt;assigned-pattern-CE&gt;::=    ?&lt;variable-symbol&gt; &lt;- &lt;pattern-CE&gt;
+&lt;pattern-CE&gt;         ::=    &lt;ordered-pattern-CE&gt; |
+                            &lt;template-pattern-CE&gt; |
+                            &lt;object-pattern-CE&gt;
+&lt;ordered-pattern-CE&gt; ::=    (&lt;symbol&gt; &lt;constraint&gt;*)
+&lt;template-pattern-CE&gt;::=    (&lt;deftemplate-name &lt;LHS-slot&gt;*)
+&lt;object-pattern-CE&gt;  ::=    (object &lt;attribute-constraint&gt;*)
+&lt;attribute-constraint&gt;  ::= (is-a &lt;constraint&gt;) |
+                            (name &lt;constraint&gt;) |
+                            (&lt;slot-name&gt; &lt;constraint&gt;*)
+&lt;LHS-slot&gt;              ::= &lt;single-field-LHS-slot&gt; |
+                            &lt;multifield-LHS-slot&gt;
+&lt;LHS-slot&gt;              ::= &lt;single-field-LHS-slot&gt; |
+                            &lt;multifield-LHS-slot&gt;
+&lt;single-field-LHS-slot&gt; ::= (&lt;slot-name&gt; &lt;constraint&gt;)
+&lt;multifield-LHS-slot&gt;   ::= (&lt;slot-name&gt; &lt;constraint&gt;*)
+</CODE></PRE>
+<P><B><U>PATTERN CONSTRAINTS</U></B></P>
+<PRE><CODE>&lt;constraint&gt;            ::= ? | $? | &lt;connected-constraint&gt;
+&lt;connected-constraint&gt;
+             ::= &lt;single-constraint&gt; |
+                 &lt;single-constraint&gt; &amp; &lt;connected-constraint&gt; |
+                 &lt;single-constraint&gt; | &lt;connected-constraint&gt;
+&lt;single-constraint&gt;     ::= &lt;term&gt; | ~&lt;term&gt;
+&lt;term&gt;               ::= &lt;constant&gt; |
+                         &lt;single-field-variable&gt; |
+                         &lt;multifield-variable&gt; |
+                         :&lt;function-call&gt; |
+                         =&lt;function-call&gt;</CODE></PRE>
+</BODY>
+</HTML>