IORef<T> class final

Mutable reference in the IO monad.

Allows having a reference that can be read and mutated inside the IO monad. Can be used in conjunction with a closure to preserve a state across multiple IO function calls, or in any other case where code is run inside an IO monad.

In most cases, the State monad should be used, and IORef must be viewed as a last resort, as it holds a mutable field inside itself that can be modified inside of the IO monad.

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

modify(Endo<T> update) → IO<Unit>

Works almost identical to the write method, but instead of taking a value that needs to be written, takes an Endo function, applies the IORef's current value to it and writes the result to the IORef.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

read() → IO<T>

Extracts a current value of the IORef and returns it inside the IO monad.

toString() → String

A string representation of this object.

inherited

write(T value) → IO<Unit>

Writes the given value to the IORef and returns a Unit inside the IO monad.

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

create<T>(T initial) → IO<IORef<T>>

Creates a new IORef inside an IO monad with a given initial value.