Title here
Summary here
Enums in AngelScript
Enumerated types (enums) are a special case of sum types. An enum is a type that has a fixed number of possible values, each with a distinct name. Angelscript doesn’t have an enum type as a distinct language feature, but enums are simple to implement using existing language idioms.
Our enum type `ServerState` has an underlying `int` type.
```angelscript
enum ServerState {
StateIdle,
StateConnected,
StateError,
StateRetrying
}The possible values for ServerState are defined as constants. The special keyword enum generates successive constant values automatically; in this case 0, 1, 2, and so on.
By implementing the Stringer interface, values of ServerState can be printed out or converted to strings.
string stateName(ServerState ss) {
switch (ss) {
case StateIdle: return "idle";
case StateConnected: return "connected";
case StateError: return "error";
case StateRetrying: return "retrying";
default: return "unknown";
}
}If we have a value of type int, we cannot pass it to transition - the compiler will complain about type mismatch. This provides some degree of compile-time type safety for enums.
void main() {
ServerState ns = transition(StateIdle);
print(stateName(ns) + "\n");
ServerState ns2 = transition(ns);
print(stateName(ns2) + "\n");
}
ServerState transition(ServerState s) {
switch (s) {
case StateIdle:
return StateConnected;
case StateConnected:
case StateRetrying:
return StateIdle;
case StateError:
return StateError;
default:
throw("unknown state: " + stateName(s));
}
}To run this script, you would typically use it within an environment that supports Angelscript. Now that we can run and build basic Angelscript programs, let’s learn more about the language.