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@ -351,7 +351,42 @@ fn main() {
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在泛型参数之前,Rust完全不适合复杂矩阵的运算,自从有了const泛型,一切即将改变。
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## const fn
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#### const泛型表达式
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假设我们某段代码需要在内存很小的平台上工作,因此需要限制函数参数占用的内存大小,此时就可以使用const泛型表达式来实现:
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```rust
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#![allow(incomplete_features)]
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#![feature(generic_const_exprs)]
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fn something<T>(val: T)
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where
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Assert<{ core::mem::size_of::<T>() < 768 }>: IsTrue,
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// ^-----------------------------^ 这里是一个const表达式,换成其它的const表达式也可以
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{
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//
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}
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fn main() {
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something([0u8; 0]); // ok
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something([0u8; 512]); // ok
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something([0u8; 1024]); // 编译错误,数组长度是1024自己,超过了768字节的参数长度限制
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}
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// ---
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pub enum Assert<const CHECK: bool> {
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//
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}
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pub trait IsTrue {
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//
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}
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impl IsTrue for Assert<true> {
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//
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}
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```
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#### const fn
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@todo
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## 泛型的性能
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