4.26 Arguments validation clauses

The clauses are meant to be used with the features of the library (vicare arguments validation); notice that the name of the clause is not the name of the exported binding.

Validation Clause: file-descriptor obj

Validation Clause: file-descriptor/false obj

Succeed if obj satisfies the file-descriptor? predicate or, for the second clause, it is #f.

Validation Clause: network-port-number obj

Validation Clause: network-port-number/false obj

Succeed if obj satisfies the network-port-number? predicate or, for the second clause, it is #f.