flex Expert System Toolkit - LPIS

7. Knowledge Specification Language 71
flex toolkit
Examples
Existence Test
the temperature \= the 'freezing point' of water
the staff are not equal to nothing
the capacity of jugA is different from jugA`s volume
A test for the existence of a variant is to decide whether or not it has a
current value. For this use either of the KSL keywords
known
unknown.
Examples
the starter of the meal is unknown
the temperature is known
Direct Comparison
A direct comparison of two terms uses the built-in typographical ordering
of Prolog terms. For comparison, use the arithmetic operators >, beta / 2
the temperature =< the 'freezing point' of water
the pupil`s mark is not below 50
the temperature is at or above boiling_point
the likelihood of frost is less than probable
the food`s calories is less than or equal to 400
Relative Comparison
The relative comparison of two terms is determined by their relative
positions within a defined group construct. The group can be specified
explicitly as an ordered set, using the KSL keywords according to, or
implicitly by name (i.e. a group previously defined).
Any of the above direct comparison operators may be used to define the
type of the comparison.