The condition method option indicates that the method is a condition, which is a declarative restricted method that returns a Boolean result. Conditions cannot be reimplemented from a superschema or superclass. You can define constant parameters for a condition that is not a constraint. Only if and return instructions can be used in condition methods.
Constraints are used in conditions to maintain automatic inverse references when the specified conditions are satisfied. Only automatic references can have a constraint. When the manual side of the inverse reference is set, the condition used as the constraint is evaluated and the automatic inverse is set only if the value of the condition is true. If the automatic reference is a
For details about defining conditions, see "
The following example shows the use of the condition option in a method signature.
isMultipleOf(d : Integer): Boolean condition; begin return 1 div d = 0; end;