process networks from Field Harrison

process_networks.fsx

//networks

let rec from x = Seq.unfold (fun x -> Some(x,x+1)) x

let rec filter n xs = Seq.filter (fun m -> (m % n) <> 0)  xs 

let rec sieve (xs:seq<int>) = 
    let m = Seq.head xs
    seq{yield m; yield! sieve <| filter m (Seq.tail xs) }
    
let incList xs = Seq.map ((+) 1) xs

let rec ints () = seq {yield 0; yield! incList <| ints()} 

let rec cycle () = seq {yield 1; yield 2; yield! cycle ()} 

let rec s2 () = 
    let ints k = seq {yield 0; yield! k}
    let s1 = seq { yield! s2() |> incList}
    ints s1
    
let f k =seq {yield 1; yield! k}
let a xs1 xs2 = Seq.zip xs1 xs2|> Seq.map (fun (a,b) -> a+b)

let rec s1 () = 
    let rec s2 () = 
        let s3 = seq{ yield! a (s1()) (s2())} 
        f s3 
    f (s2())