Rust mdo is a monadic do notation using macro and duck typing. It
provides a syntax extention providing something looking like the
Haskell do notation, and rewrite it using a bind
function. Some
functions are privided for some common monadic structures.
Add to your Cargo.toml
:
[dependencies]
mdo = "*"
#[macro_use] extern crate mdo;
fn main() {
// exporting the monadic functions for the Iterator monad (similar
// to list comprehension)
use mdo::iter::{bind, ret, mzero};
// getting the list of (x, y, z) such that
// - 1 <= x <= y < z < 11
// - x^2 + y^2 == z^2
let l = bind(1i32..11, move |z|
bind(1..z, move |x|
bind(x..z, move |y|
bind(if x * x + y * y == z * z { ret(()) }
else { mzero() },
move |_|
ret((x, y, z))
)))).collect::<Vec<_>>();
println!("{:?}", l);
// the same thing, using the mdo! macro
let l = mdo! {
z =<< 1i32..11;
x =<< 1..z;
y =<< x..z;
when x * x + y * y == z * z;
ret ret((x, y, z))
}.collect::<Vec<_>>();
println!("{:?}", l);
}
You can find the rustdoc here.
This work is free. You can redistribute it and/or modify it under the terms of the Do What The Fuck You Want To Public License, Version 2, as published by Sam Hocevar. See the COPYING file for more details.