Last active
July 3, 2022 07:19
-
-
Save sahandevs/0bf0bf448fc4324b5b3089c11383a5f6 to your computer and use it in GitHub Desktop.
Compile-time safe Builder pattern / idea: https://github.com/maminrayej
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
pub mod ItemBuilder { | |
pub struct ItemBuilder<const A_SET: bool, const C_SET: bool, const F_SET: bool> { | |
a: Option<usize>, | |
b: Option<usize>, | |
c: Option<usize>, | |
d: Option<usize>, | |
e: Option<usize>, | |
f: Option<usize>, | |
} | |
pub fn new() -> ItemBuilder<false, false, false> { | |
ItemBuilder { a: None, b: None, c: None, d: None, e: None, f: None } | |
} | |
impl<const A: bool, const B: bool, const F: bool> ItemBuilder<A, B, F> { | |
pub fn a(self, value: usize) -> ItemBuilder<true, B, F> { | |
ItemBuilder { | |
a: Some(value), | |
b: self.b, | |
c: self.c, | |
d: self.d, | |
e: self.e, | |
f: self.f, | |
} | |
} | |
pub fn b(mut self, value: usize) -> Self { | |
self.b = Some(value); | |
self | |
} | |
pub fn c(self, value: usize) -> ItemBuilder<A, true, F> { | |
ItemBuilder { | |
a: self.a, | |
b: self.b, | |
c: Some(value), | |
d: self.d, | |
e: self.e, | |
f: self.f, | |
} | |
} | |
pub fn d(mut self, value: usize) -> Self { | |
self.d = Some(value); | |
self | |
} | |
pub fn e(mut self, value: usize) -> Self { | |
self.e = Some(value); | |
self | |
} | |
pub fn f(self, value: usize) -> ItemBuilder<A, B, true> { | |
ItemBuilder { | |
a: self.a, | |
b: self.b, | |
c: self.c, | |
d: self.d, | |
e: self.e, | |
f: Some(value), | |
} | |
} | |
} | |
impl ItemBuilder<true, true, true> { | |
pub fn build(self) -> super::Item { | |
unsafe { | |
super::Item { | |
a: self.a.unwrap_unchecked(), | |
b: self.b, | |
c: self.c.unwrap_unchecked(), | |
d: self.d, | |
e: self.e, | |
f: self.f.unwrap_unchecked(), | |
} | |
} | |
} | |
} | |
} | |
pub struct Item { | |
pub a: usize, | |
pub b: Option<usize>, | |
pub c: usize, | |
pub d: Option<usize>, | |
pub e: Option<usize>, | |
pub f: usize, | |
} | |
fn test() { | |
let builder = ItemBuilder::new() | |
.a(1) | |
.c(3) | |
.a(3) | |
.f(4) | |
.a(1) | |
.build(); | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment