antimonia/mutable

The mutable module allows you to use mutable values of any type within your code.

Types

Mutable

The Mutable generic type houses a reference to the value of the specified type stored elsewhere in memory.

Implementation notes:

On JavaScript, Mutable(a) values correspond to an object of type { value: a }. This may be subject to change, so if you (for some reason) are writing bindings in JavaScript that requires the Mutable type, please don’t use this.
On Erlang, mutability is achieved through a process that is sent get or set operations, and loops with a new value.

pub type Mutable(a)

Values

from

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pub fn from(value: a) -> Mutable(a)

Creates a Mutable from a value.

get

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pub fn get(mut: Mutable(a)) -> a

Gets the value of a Mutable.

set

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pub fn set(mut: Mutable(a), value: a) -> Nil

Updates the value of a Mutable.

to_tuple

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pub fn to_tuple(mut: Mutable(a)) -> #(fn() -> a, fn(a) -> Nil)

Converts a Mutable to a #(getter, setter) tuple.

Example

fn update_mutable_handler(mut: Mutable(Int)) -> Nil {
  let #(val, set_val) = to_tuple(mut)
  case val() {
    0 -> set_val(2)
    _ -> set_val(0)
  }
}

tuple_from

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pub fn tuple_from(value: a) -> #(fn() -> a, fn(a) -> Nil)

Creates a #(getter, setter) tuple from a value.

Example

let #(counter, set_counter) = tuple_from(3)

counter()
// -> 3
set_counter(counter() + 2)
// -> Nil
counter()
// -> 5