Explanation block is invoked after every decision taken by expert system. In explanation block module there is a
default rule whose LHS field is empty and every time when Explanation block is invoked this rule gets executed. The
RHS field of this rule consists File constructs, which will be used to open all the fire(no).dat files and assign the values to
variable called var(no5), using this var(no) variable, Fact -(rule ?var(no)) gets asserted. This is the initial fact of
explanation block. Salience - construct of CLIPS 6.0 is used to set priority of execution for rules. The default rule in
explanation block has the highest salience value (1000). Other rules have the salience value in decreasing order i.e., if
r1.......rn is set of rules stored in working memory of Explanation Block then