Any Function Added to the Rel Standard Library
George Kastrinis
06 October 2021
less than a minute read
The Standard Library now offers the Any function. This is a unary relation that is true for any value used. It is used as a generic type assertion that always succeeds.
In the following example, we define a relation R that contains tuples of various lengths (arities). In the second line we output the second argument of all the tuples in R that have arity 3. By using Any in the first and third position, we declare that we are not interested in the values of these arguments:
def R = {(1, 2, 3); ("a", 3, 0.5); (11, 22, 33, 44)}
def output = x : R(Any, x, Any)Relation:
| 2 |
| 3 |
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