5 releases

0.1.4 Dec 2, 2023
0.1.3 Nov 28, 2023
0.1.2 Nov 28, 2023
0.1.1 Nov 28, 2023
0.1.0 Nov 28, 2023

#2191 in Rust patterns

MIT license

7KB
125 lines

scalar_map

map for scalar types.

let num: Option<i32> = Some(42);
assert_eq!(num.map(|x| 42 - x), Some(0));

let num: i32 = 42;
assert_eq!(num.map(|x| 42 - x), 0);

let num: Option<i32> = Some(42);
assert_eq!(num.and_then(Option::Some), Some(0));

let num: i32 = 42;
assert_eq!(num.and_then(Option::Some), Some(0));

What does it solve

  • You can still keep map and and_then intact even if Option is refactored out.

  • You want

    x.map(Mutex::new).map(Arc::new)
    

    ...instead of

    Arc::new(Mutex::new(x))
    

Custom struct

Deriving

# Run this to add the `derive` feature
cargo add scalar_map --features derive
#[derive(Debug, PartialEq, ScalarMap)]
struct MyNum(i32);

let num = MyNum(42);
assert_eq!(num.map(|x| 42 - x.0).map(MyNum), MyNum(0));

Without deriving

#[derive(Debug, PartialEq)]
struct MyNum(i32);
impl ScalarMapExt for MyNum {}

let num = MyNum(42);
assert_eq!(num.map(|x| 42 - x.0).map(MyNum), MyNum(0));

Dependencies

~105KB