9.3 Passing traits as arguments

The contract-call function enables contracts to call each other. We have been using it to manually interact with our contracts during the interactive BigBang session provided by the REPL and BigBangNet. The function takes two arguments: the contract identifier and the function name, followed by zero or more parameters. We discovered that the contract identifier can be either a short form or a fully qualified contract principal. However, there is also a third type of contract identifier, known as a trait reference.