Select

Calibre supports select for channel-based concurrency.

select lets the program react to whichever channel operation is ready first.

select {
  value <- results => {
    print(value);
  },
  job <- jobs => {
    print(job);
  },
  _ => {}
};

This is especially useful when working with channels inside concurrent loops.

for  => {
  select {
    value <- results => {
      print("received => " & value);
    },
    _ => {
      break;
    }
  };
};

The wildcard arm _ => { ... } acts as a fallback branch.

select is most commonly used where the program needs to receive values as they become available instead of polling channels manually.