ThunkWrapper

fp_library::classes::thunk_wrapper

Trait ThunkWrapper 

Source 
pub trait ThunkWrapper {
    type Cell<T>;

    // Required methods
    fn new<T>(value: Option<T>) -> Self::Cell<T>;
    fn take<T>(cell: &Self::Cell<T>) -> Option<T>;
}
Expand description

Trait for pointers that can wrap a thunk with interior mutability.

This is used by Lazy to store the thunk and clear it after execution.

Required Associated Types§

Source

type Cell<T>

The cell type used to store the thunk.

Required Methods§

Source

fn new<T>(value: Option<T>) -> Self::Cell<T>

Creates a new cell containing the value.

§Type Signature

forall a. Option a -> Cell a

§Type Parameters
  • T: The type of the value.
§Parameters
  • value: The value to wrap.
§Returns

A new cell containing the value.

§Examples
use fp_library::{brands::*, functions::*};

let cell = thunk_wrapper_new::<RcBrand, _>(Some(42));
assert_eq!(thunk_wrapper_take::<RcBrand, _>(&cell), Some(42));
Source

fn take<T>(cell: &Self::Cell<T>) -> Option<T>

Takes the value out of the cell.

§Type Signature

forall a. Cell a -> Option a

§Type Parameters
  • T: The type of the value.
§Parameters
  • cell: The cell to take the value from.
§Returns

The value if it was present, or None.

§Examples
use fp_library::{brands::*, functions::*};

let cell = thunk_wrapper_new::<RcBrand, _>(Some(42));
assert_eq!(thunk_wrapper_take::<RcBrand, _>(&cell), Some(42));
assert_eq!(thunk_wrapper_take::<RcBrand, _>(&cell), None);

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§