Types

Primitive Types

Lake currently supports three primitive types:

All values are represented as i64 at the machine code level. Strings are stored as read-only data with fat pointers. Process identifiers are heap pointers that remain stable for the lifetime of the process.

Type Annotations

Types appear in patterns:

n i64                 # 64-bit integer

And in default values:

_ i64.0               # i64 with default value 0

Type-Based Dispatch

Types are central to branch dispatch. When a machine is called, the compiler matches the argument types against branch signatures:

counter is {
  n i64 -> { ... }   # matches calls with one i64 argument
}

The hash of argument types determines which branch receives the call. This dispatch is O(1) at runtime.

Process Identifiers (pid)

The pid type represents a handle to a spawned process. When a machine is called, it returns a pid that can be used to send messages to that process:

receiver is {
  _ i64.0 -> {
    wait { n i64 -> { rt_write(1 "got message\n" 12) } }
  }
}

main is {
  _ i64.0 -> {
    let p pid = receiver()
    p(42)                    # send message to receiver
  }
}

A pid is a stable heap pointer that identifies the process for its entire lifetime. It can be stored in variables, passed as arguments, and sent through mailboxes.