Constrain Values That Your User Can Select
Use the constrain keyword to apply a constraint at run time when the user manually selects an option or enters a value.
- You can use the constrain keyword at the beginning of a constrain statement.
- A constrain statement uses an expression to constrain a relationship.
- You don't have to have a constrain keyword in a constrain statement.
You can include only one of these operators in each constrain statement:
- Requires
- Negates
- Implies
- Excludes
Here's an example of a constrain statement that uses the constrain keyword.
CONSTRAIN a IMPLIES b;
CONSTRAIN (a+b) * c > 10 NEGATES d;
Here's an example that doesn't use constrain.
a IMPLIES b;
(a + b) * c > 10 NEGATES d;
Here's an example constrain statement that uses FOR ALL...IN with an iterator.
CONSTRAIN F1 DEFAULTS &var1
FOR ALL &var1 IN F1.Options();
Here's what it means in pseudocode:
If your user selects one option in the F1 feature, then select all other options in
the F1 feature.