Function monster::incubation::map_ref_mut::map_ref_mut

pub unsafe fn map_ref_mut<T, F>(thing: &mut T, f: F) where
    F: FnOnce(T) -> T, 

Map the value of a mutable reference. Useful if you want to apply a FnOnce(T) -> T to a &mut T. This function is unsafe because panicking in f would leave the pointee uninitialized.

Example

use monster::incubation::map_ref_mut;

let foo = &mut 123;

unsafe { map_ref_mut(foo, |n| n + 654) }

assert_eq!(*foo, 777);