Structs

Define a named struct with type:

type Point = {Integer x, Integer y}
type Person = {String name, Integer age}

Instantiation

Use StructName { field: value, ... } to create an instance:

let p = Point { x: 10, y: 20 }
let alice = Person { name: "Alice", age: 30 }

Field access

print(alice.name)   // Alice
print(alice.age)    // 30

Field assignment

alice.age = 31

Shared structs

Prefix with $ or shared to make the whole struct shared across threads.

shared bob = Person { name: "Bob", age: 25 }

def birthday($Person p):
    p.age = p.age + 1

spawn birthday(bob)

Individual fields cannot be marked shared, share the whole struct instead.

Structs and threads

Structs are copied when passed to a spawned function. Use shared only if the thread needs to mutate the same instance the caller holds.