Anonymous user
Algebraic data types: Difference between revisions
→{{header|Rust}}: Added Rust
SqrtNegInf (talk | contribs) m (→{{header|Perl 6}}: slip needed in 'insert' routine) |
(→{{header|Rust}}: Added Rust) |
||
Line 1,088:
rascal>/a.c/ := "abc";
bool: true</lang>
=={{header|Rust}}==
{{trans|Haskell}}
This would be a horribly inefficient way to implement a Red-Black Tree in Rust as nodes are being allocated and deallocated constantly, but it does show off Rust's pattern matching.
<lang rust>#![feature(box_patterns, box_syntax)]
use self::Color::*;
use std::cmp::Ordering::*;
enum Color {R,B}
type Link<T> = Option<Box<N<T>>>;
struct N<T> {
c: Color,
l: Link<T>,
val: T,
r: Link<T>,
}
impl<T: Ord> N<T> {
fn balance(col: Color, n1: Link<T>, z: T, n2: Link<T>) -> Link<T> {
Some(box
match (col,n1,n2) {
(B, Some(box N {c: R, l: Some(box N {c: R, l: a, val: x, r: b}), val: y, r: c}), d)
| (B, Some(box N {c: R, l: a, val: x, r: Some (box N {c: R, l: b, val: y, r: c})}), d)
=> N {c: R, l: Some(box N {c: B, l: a, val: x, r: b}), val: y, r: Some(box N {c: B, l: c, val: z, r: d})},
(B, a, Some(box N {c: R, l: Some(box N {c: R, l: b, val: y, r: c}), val: v, r: d}))
| (B, a, Some(box N {c: R, l: b, val: y, r: Some(box N {c: R, l: c, val: v, r: d})}))
=> N {c: R, l: Some(box N {c: B, l: a, val: z, r: b}), val: y, r: Some(box N {c: B, l: c, val: v, r: d})},
(col, a, b) => N {c: col, l: a, val: z, r: b},
})
}
fn insert(x: T, n: Link<T>) -> Link<T> {
match n {
None => Some(box N { c: R, l: None, val: x, r: None }),
Some(n) => {
let n = *n;
let N {c: col, l: a, val: y, r: b} = n;
match x.cmp(&y) {
Greater => Self::balance(col, a,y,Self::insert(x,b)),
Less => Self::balance(col, Self::insert(x,a),y,b),
Equal => Some(box N {c: col, l: a, val: y, r: b})
}
}
}
}
}<lang rust>
=={{header|Scala}}==
| |||