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