Data Types

Every value in Acton is of a certain data type. The type specifies what kind of data is being specified and how to work with that data.

Acton supports a plethora of primitive data types.

• integers, like 1, 2, 123512, -6542 or 1267650600228229401496703205376
  • int is arbitrary precision and can grow beyond machine word sizes
  • i16, i32, i64, u16, u32, u64 are fixed size integers
• float 64 bit float, like 1.3 or -382.31
• bool boolean, like True or False
• str strings, like foo
  • strings support Unicode characters
• lists like [1, 2, 3] or ["foo", "bar"]
• dictionaries like {"foo": 1, "bar": 3}
• tuples like (1, "foo")
• sets like {"foo", "bar"}

In Acton, mutable state can only be held by actors. Global definitions in modules are constant. Assigning to the same name in an actor will shadow the global variable.

foo = 3

def printfoo():
    print("global foo:", foo)

actor main(env):
    foo = 4

    print("local foo:", foo)
    printfoo()

    a = u16(1234)
    print("u16:", a)

    env.exit(0)

Output:

local foo, shadowing the global foo: 4
global foo: 3
u16: 1234