flex Expert System Toolkit - LPIS

7. Knowledge Specification Language 103
the type of the answer, using the KSL keywords such that.
The following example expects an integer greater than 18 for the age. Error
messages will be given if the input does not comply with these conditions.
question age_of_applicant
Please enter your age ;
input X such that integer( X ) and X > 18 .
User Defined Questions
Groups
The flex programmer may define alternative ways of getting information
from the user. The KSL keywords
answer is ... such that
may be used to specify another routine which will provide the necessary
information. This routine may be a flex relation, a flex action or a
Prolog program, probably one which presents a customised dialog into
which the user will enter data.
The general format of a user-defined question is as follows.
question question_name
answer is Value
such that directive .
Example
question wine
answer is X such that get_wine_from_user( X ) .
The get_wine_from_user/1 routine will be defined elsewhere and will
return in X the wine chosen by the user.
A group is a means of gathering several names under one collective
heading. The basic format of a group is:
group group_name
first_item, second_item, .., last_item .
A group may simply be a set of items grouped together for convenience, for
use in a question.
Example
group wall_colours
magnolia, coffee, apple_white, barley, buttermilk .
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