1.9 KiB
Records
Records may be defined. Each record contains one or more named fields. Note that records are just tuples with named fields. In many ways, the two can be interchanged.
record Foo is (x: String, y: Int32)
Record fields are both ordered and named.
- Anonymous Records
- Generic Records
- Instantiating Records
- Copying Data
- Accessing Record Data
- Tuple Interactions
- Destructuring Records
Anonymous Records
Records do not need to be named.
(x: String, y: String, z: String)
Generic Records
Records may have generically typed data, and accept a type constructor:
record Foo[A, B] is (x: A, y: B)
Instantiating Records
record Foo is (x: String, y: Int32)
let foo1 := Foo("foo", 1)
let foo2 := Foo(x := "foo", y := 1)
Copying Data
Copy syntax allows any record to be duplicated, with any fields explicitly overridden by some value:
record Foo is (x: String, y: Int32)
let foo := Foo("foo", 1)
let bar := copy(foo)
let baz := copy(foo, ("y": 2))
Accessing Record Data
The . operator is used to access individual fields on a record.
record Foo is (x: String, y: Int32)
let foo := Foo("foo", 1)
let bar := foo.x
Note that because records are just tuples, tuple syntax continues to work:
let baz: Int32 := foo._2
Tuple Interactions
Use the following record definition for this section:
record Foo is (x: String, y: Int32)
Tuples can be assigned from records.
let foo := Foo("foo", 1)
let some_tuple: (String, Int32) := foo
Records can be assigned from tuples.
let some_tuple := ("foo", 1)
let foo: Foo := some_tuple
Destructuring Records
Records can be destructured via pattern matching capabilities. This can take two possible forms.