Conditional

The ? conditional operator allows us to match on expressions, replacing the if/else constructs in most languages. This also includes handling return values from functions.

Syntax:

expression ? {
  patterns
}

Example:

read(file) ? { // returns (data, err)
  _, err => {
    print(err)
    return -1
  }
  data, _ => print(data)
}

In this example:

• The result of read(file) is evaluated by the pattern expressions, mapping into data and err accordingly
• If an error is present, the conditional returns from the enclosing function