Records

Joe supports record types, similar to Java's record types.

record Person(first, last) {
    method fullName() {
        return this.first + " " + this.last;
    }
    ...
}

var joe = Person("Joe", "Pro");
println(joe.first);         // Prints "Joe"
println(joe.last);          // Prints "Pro"
println(joe.fullName());    // Prints "Joe Pro"
println(joe);               // Prints "Person(Joe, Pro)"

Like a Java record, a Joe record is immutable, having only the fields defined in the record declaration.

In most ways, a record type is just like a class. That is, a record type may have:

• methods
• static methods
• static fields
• a static initializer

A record type differs from a class in the following ways:

• Its fields are immutable, and no new fields may be added dynamically.
• Its fields have a well-defined order.
• Instances are initialized automatically; no init method is required.
• The record type's init method, if it has one, has no special semantics; it's just another method.
• A record type cannot extend another type or be extended by another type.

See the Classes section for more information on methods, etc.

Records and Pattern Matching

Record types are especially useful when pattern matching is used.