bad-optics/examples/convoluted.rs

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2021-11-11 21:54:00 +00:00
use bad_optics::{lenses::*, prisms::*, traversals::*};
#[derive(Debug, PartialEq, Clone)]
struct MyStruct {
hey: (u8, (u8, [Option<i32>; 5])),
}
fn main() {
// make a lens that accesses `hey` in `MyStruct`
let hey = lens(
|hello: MyStruct| hello.hey,
|mut hello: MyStruct, v| {
hello.hey = v;
hello
},
);
// the thing we want to access
let thing: (MyStruct, &'static str) = (
MyStruct {
hey: (1, (2, [None, Some(1), Some(2), None, Some(4)])),
},
"hello",
);
let array_lens = _0 // access the first element in the tuple
+ hey // access hey
+ _1 // access the second element in the tuple
+ _1; // access the second element in the tuple
assert_eq!(array_lens(thing.clone()).len(), 5);
let lens = array_lens
+ each // access each element of the [Option<i32>; 5] array
+ _Some; // access the ones that are Some;
assert_eq!(lens(thing.clone()), vec![1, 2, 4]);
assert_eq!(
lens(thing, |v| v + 10),
(
MyStruct {
hey: (1, (2, [None, Some(11), Some(12), None, Some(14)])),
},
"hello",
)
);
}