flex Expert System Toolkit - LPIS

7. Knowledge Specification Language 107
Examples
template on_top_of
block ^ is on top of ^ ;
block ^ is not on top of ^ .
Having defined the on_top_of template, we can then use it in KSL
statements. For example, the following statement
block p is on top of the table
will be converted at compile time to the term
on_top_of( p, table )
The statement
block q is not on top of p
will be converted at compile time to the term
not on_top_of( q, p ).
The following template defines price comparisons of items. The phrase
is more expensive than is the positive template, with is cheaper
than being the negative template.
template price_greater
^ is more expensive than ^ ;
^ is cheaper than ^ .
Thus the expression X is more expensive than Y will translate at
compile time to price_greater( X, Y ), and A is cheaper than
B will translate at compile time to not price_greater( A, B ).
We may define the relation price_greater/2 as follows.
relation Item1 is more expensive than Item2
if the price of Item1
is greater than the price of Item2.
Note that
Item1 is more expensive than Item2
translates at compile time to
price_greater( Item1, Item2 ).
flex toolkit
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