operational::seq!

macro_rules! seq {

    (let $p: pat = $e: expr ; $( $t: tt )*) => (
        { let $p = $e ; seq! { $( $t )* } }
    );

    (let $p: ident : $ty: ty = $e: expr ; $( $t: tt )*) => (
        { let $p: $ty = $e ; seq! { $( $t )* } }
    );

    (for $p: pat = $e: expr ; $( $t: tt )*) => (
        $e.and_then(move |$p| seq! { $( $t )* } )
    );

    (for $p: ident : $ty: ty = $e: expr ; $( $t: tt )*) => (
        $e.and_then(move |$p : $ty| seq! { $( $t )* } )
    );

    ($f: expr) => ($f)

}

Provides a convient syntax for monadic computations.

Example

#[macro_use] extern crate operational;
use operational::point;
use operational::instr::identity;
fn main() {
    let l = seq!{
        for x = point(42);
        for _ = point(0);
        let y = x + 5;
        point(y + 5)
    };
    assert_eq!(l, identity(52));
}